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HA.ND-BOOK 



OF 



Land and Marine Endnes, 



INCLUDING 



THE MODELLING, CONSTRUCTION, RUNNING, AND 

MANAGEMENT OF LAND AND MARINE 

ENGINES AND BOILERS. 



lj)it| )((Itt$italimt3. 



BY 

STEPHEN ROPER, Ekgineer, 

Author of 
' Roper's Catecliism of High Pressure or Non-Condejis«ig"5TigiT*^^' 

" Roper's Hand-Book of the Locomotive," ieje- ^'^' 0("j t^N^ 



PHILADELPHIA: 
CLAXTON, EEM8EN & HAFFELFINGER, 

624, 626 & 628 MARKET STREET. 

1875. 






Entered according to Act of Congress, in the year 1875, by 

STEPHEN ROPER, 

in the Office of the Librarian of Congress, at Washington. 



^-^3- 



5^ 

6 



^•-J 

:)'' 



I, philad'a. fe<:^^^'^ 



J. FAGAN 
ELECTR0TYPER8, 



Seiheimer &, Moore, Printers- 
501 Chestnut Street. 



TO THE 



ENGINEERS OF THE UNITED STATES, 



THIS BOOK 



" Steam Engineering is one of the noblest sciences that 
ever attracted the attention of manP 



1* 




"A place for everything and everything In Its place."— See page 264. 

vi 



INTRODUCTION. 



n[^HE object of the writer in preparing this work has 
-L been to present to the practical engineer a book to 
which he can refer with confidence for information regard- 
ing every branch of his profession. Many of the books 
heretofore written on this subject are full of formulae for 
calculating questions that may arise in the engine-room ; 
but, as they are generally expressed in algebraical form, 
they are of little service to the majority of engineers ; for, 
however useful such formulae may be to the scientific, they 
can be of no practical value to men who do not fully 
understand them. It is also no less a fact that nearly all 
writers on the steam-engine deal more with the past than 
the present. This is to be regretted, for, however inter- 
esting the bygone records of steam engineering may be, as 
a history, they cannot instruct the engineer of the present 
day in the principles and practice of his profession. 

An experience of over thirty years with all kinds of 
engines and boilers enables the writer to fully comprehend 
the wants of the class for whom^. he writes, and what they 
can understand and employ. With this object in view, 
' he has carefully investigated all the details of Land and 
Marine Engines and Boilers, taking up each subject singly, 
and excluding therefrom everything not directly connected 
with Steam Engineering. Particular attention has been 
given to the latest improvements in all classes of engines, 

vii 



Vlll INTRODUCTION. 

and to their proportions according to the best modern prac- 
tice, which will be found of special value to engineers, as 
nothing of the kind has heretofore been published. The 
book also contains ample instructions for setting up, lining, 
reversing, and setting the valves of all classes of engines, 
— subjects that have not, up to the present time, received 
that attention from writers on the steam-engine that their 
importance to engineers so justly merits. It also contains 
a complete Lexicon of Central, Mechanical, and Natural 
Forces, which will be found of great value to engineers, as 
scarcely anything of the kind that has heretofore been 
published, has been applicable to American practice. A 
large portion of the work is devoted to the examination 
and discussion of the principles of Hydro- and Thermo- 
dynamics, which include Air, Water, Heat, Combustion, 
Steam, Liquefaction, Dilatation of Gases, Molecular and 
Atomic Forces, Dynamic Equivalents, subjects with which 
the practical engineer should be fully conversant ; as to 
ignore the principles of any subject is similar to building 
a structure without knowing the strength of the foundation ; 
for it was only by a minute and careful analysis of the 
physical phenomena which convert heat into a motor force 
that the steam-engine has been brought to its present per- 
fection. The strength of materials, design, construction, 
care, and management of all classes of Steam-Boilers are 
also fully discussed. 

The writer candidly admits that the work may be found 
somewhat defective in language, but he firmly believes 
that it will be found perfectly accurate and reliable in all 
other respects. 

S. R 



CONTENTS. 



F(yr a full reference to the Contents in detail, see Index, page 583, 

PAGE 

Introduction . . .7 

The Steam-engine . 21 

Steam . .25 

Table showing the Temperature and Weight of Steam 
at different Pressures from 1 Pound per Square Inch 
to 300 Pounds, and the Quantity of Steam produced 
from 1 Cubic Inch of Water, according to Pressure . 39 

Working Steam expansively 43 

Table of Hyperbolic Logarithms to be used in Connec- 
tion with the above Eule 48 

Table showing the average Pressure of Steam upon the 
Piston throughout the Stroke, when Cut-off in the 
Cylinder from J to y\> commencing with 25 Pounds 
and advancing in 5 Pounds up to 75 Pounds Press- 
ure 49 

Table showing the average Pressure of Steam upon the 
Piston throughout the Stroke, when Cut-off in the 
Cylinder from \ to J, commencing with 80 Pounds 
and advancing in 5 Pounds up to 130 Pounds Press- 
ure .... 50 

Table of Multipliers by which to find the mean Pressure 
of Steam at various points of Cut-off. . . .51 
High-pressure or Non-condensing Steam-engines . 54 

Power of the Steam-engine 55 

ix 



X CONTENTS. 

PAGE 

Foreign Terms and Units for Horse-power . . .59 

Table of Factors 68 

Waste in the Steam-engine 70 

Design of Steam-engines 73 

The Bed-plate 74 

Cylinders 74 

Table showing the proper Thickness for Steam-cylinders 

of different Diameters 75 

Pistons . . 76 

Piston-rings 77 

Piston-springs. ,77 

Steam-pistons 78 

Solid Pistons . 78 

Table of Piston Speeds for all Classes of Engines — Sta- 
tionary, Locomotive, and Marine . . . .79 
Piston, Connecting-rod, and Crank Connection . 80 
Table showing the Position of the Piston in the Cyl- 
inder at different Crank - angles, according to the 

length of Connecting-rod 81 

Table showing Length of Stroke and Number of Revolu- 
tions for different Piston Speeds in Feet per Minute . 82 

Piston-rods 83 

Crank-pins 83 

Table showing the Angular Position of the Crank-pin 
corresponding with the various Points in the Stroke 
which the Piston may occupy in the Cylinder . . 84 

Steam-chests . .85 

Valve-rods 85 

Guides 85 

Rock-shafts S6 

Cross-heads S6 

Steam-ports . .87 

Table showing the Proper Area of Steam-ports for dif- 
ferent Piston Speeds 88 

Slide-valves .89 

Proportions of Slide-valves 93 



CONTENTS. Xi 

PAGE 

Lap on the Slide-valve. . . . . , .93 

Poppet ok Conical Valves . . . . . . 95 

Table showing the Amount of "Lap" required for Slide- 
valves of Stationary Engines when the Steam is to be 

Worked expansively 97 

Lead of the Slide-valve .97 

Clearance . . .99 

Compression < . . . 100 

Friction of Slide-valves 100 

Balanced Slide-valves 102 

Fitting Slide-valves . . . . . . . 103 

Slide-valve Connections ...... 103 

Eccentrics , • . . .104 

Eccentric- RODS 108 

Cranks 109 

Crank-shafts 114 

Pillow-blocks, or Main Bearings .... 114 
Fly-wheels . . . . . . . . . 115 

Link-motion 116 

Proportions of Steam-engines according to the 

BEST Modern Practice 121 

Setting up Engines 127 

Dead-centre 128 

How TO PUT AN Engine in Line . . . . . 128 

How TO Eeverse an Engine 131 

Setting Valves 131 

How TO set A Slide-valve 132 

Setting out Piston Packing 134 

Piston- and Valve-rod Packing 185 

Cut-offs 138 

Governors 139 

The Huntoon Governor 140 

The Allen Governor 142 

The Cataract 145 

Wright's High-pressure Engine 146 

Hawkins and Dodge's High-pressure Engine . 147 



Xll CONTENTS. 

PAGE 

Watts and Campbell's High-pressure Engine . . 148 
The Buckeye High-pressure Engine . . . . 148 
Wheelock's High-pressure Engine . . . .151 
The Corliss High-pressure Engine . . . .151 
Hampson and Whitehill's High-pressure Engine . 153 
The Allen High-pressure Engine ... . .155 
Woodruff & Beach's High-pressure Engine . . 156 
Naylor's Vertical High-pressure Engine '. . 157 
Williams' Vertical Three-cylinder High-press- 
ure Engine 158 

Eoper's Caloric Engine 159 

Haskins' Vertical High-pressure Engine . . 163 
Massey's Rotary Engine . . . . . . 164 

Portable Engines 166 

How to balance Vertical Engines . . . . 166 

Knocking in Engines 168 

The Injector 169 

Method of working the Self-adjusting Injector 

WHEN Required to Lift the Water . . . 172 
Method of working the Adjustable Injector when 

Required TO Lift THE Water . . . . 173 

Instructions for Setting up Injectors . . . 173 

Temperature of Feed- water . . * . . .176 

Table of Capacities of Injectors ..... 177 

Temperature of Feed-water 177 

Pumps 178 

Steam-pumps 180 

The Dayton Cam-pump 181 

Directions for setting up Steam-pumps . . . 184 

The Pulsom^ter 185 

James Watt 187 

Condensing, or Low-pressure Steam-engines . . 188 
Explanation of the working Principles of the 

Condensing Engine 190 

Horse-power of Condensing Engines . . . .191 
The Vacuum 193 



CONTENTS. Xlll 

PAGE 

Marine Steam-engines . . . . . . .197 

Compound Engines 200 

Direct- ACTING Engines 203 

Balancing the Momentum of Direct-acting En- 
gines -- . . . 205 

Oscillating Engines . 205 

Trunk Engines . . 207 

Geared Engines . . 207 

Back-action Engines 208 

Side-lever Engines 209 

Beam Engines 209 

Marine Beam Engine 211 

Starting-gear for Marine Engines .... 215 

Condensers . . . 216 

Air-pumps 222 

The Hydrometer, Salinometer, or Salt-gauge . 223 

The Manometer , . . 224 

The Barometer . . . . * . . . 225 
Marine Engine Register, Clock, and Vacuum 
Gauge ..... ... 226 

Steam-gauges 227 

Glass Water-gauges . . . .... . 233 

The Steam-engine Indicator 235 

Method of Applying the Indicator .... 241 

Form of Diagrams , 250 

How TO keep the Indicator in Order . . . 252 

The Dynamometer , . 254 

The Engineer 256 

Management of Land and Marine Engines . . 258 

How TO PUT THE ENGINES IN A STEAMBOAT OR ShIP . 265 

Screw-propellers 271 

Negative Slip of the Screw-propeller . . . 274 

Table of the Proper Proportions of Screw-propellers . 279 

Measurement of the Screw-propeller . . . 279 

How TO Line up a Propeller-shaft .... 282 

Paddle-wheels 282 

2 



xiv CONTENTS. 

/ 

PAGE 

Fluid Eesistance . 287 

Signification of Signs used in Calculations . . . 291 

Decimal . . .291 

Decimal Equivalents of Inches, Feet, and Yards . . 292 
Decimil Equivalents of Pounds and Ounces . . . 292 
Useful Numbers in calculating Weights and Measures, 
etc. ... . ... . . .292 

Decimal Equivalents to the "Fractional Parts of a Gallon 
or an Inch . . . . . . . . . 294 

Units. . . . . 294 

Theory OF the Steam-engine 298 

Water 299 

Table showing the Weight of Water . . . .805 

Table showing the Weight of Water at different Tem- 
peratures .... . . . . . 305 

Table showing the Boiling-point for Fresh Water at 
different Altitudes above Sea-level . . . . 306 

Table showing the Weight of Water in Pipe of various 

Diameters 1 Foot in Length 307 

Air 309 

Table showing the Weight of the Atmosphere in 
Pounds, Avoirdupois, on 1 Square Inch, corre- 
sponding with different Heights of the Barometer, 
from 28 Inches to 31 Inches, varying by Tenths 

of an Inch * . . . . 311 

Table showing the Expansion of Air by Heat, and the 
Increase in Bulk in Proportion to Increase of Tem- 
perature . . 312 

The Thermometer 313 

Comparative Scale of Centigrade, Fahrenheit, and 

Reaumer Thermometers 314 

Elastic Fluids . . . . . . . . 320 

Caloric 321 

Heat 323 

Latent Heat of Various Substances .... 331 
Table of the Radiating Power of different Bodies . . 831 



coiirrENTS. XV 

PAGE 

Table showing the Effects of Heat upon different 

Bodies .332 

Combustion . . . 332 

Composition of different Kinds of Anthracite Coal . 336 
Table showing the Total Heat of Combustion of various 
Fuels . . .. .. . . . . . . 342 

Table showing the Nature and Value of several Varie- 
ties of American Coal and Coke, as deduced from Ex- 
periments by Professor Johnson, for the United 
States Government ... . . . . . 34c 

Table showing some of the Prominent Qualities in the 

principal American Woods 344 

Table showing the Kelative Properties of good Coke, 
Coal, and Wood. . . ... . . . / . . 344 

Table of Temperatures required for the Ignition of dif- 
ferent Combustible Substances , . . . . 345 

Gases . . . . 346 

Steam-boilers 350 

Steam-domes . . . . . , . , . . . . 353 

Mud-drums 355 

Setting Boilers 356 

Expansion and Contraction of Boilers . . . 358 
Testing Boilers . . . . . . . . 359 

Neglect of Steam-boilers 362 

Care and Management of Steam-boilers . . 363 
Heating Surface . ..... . . 369 

Kules for finding the Heating Surface of Steam- 
boilers .371 

Evaporative Efficiency of Boilers . . . . 372 

Horse-power of Boilers 375 

Firing . . 378 

Instructions for Firing . . . ... 382 

EuLES for finding the Quantity of Water Boilers 
AND other Cylindrical Vessels are capable 
of Containing .... . . . . 386 

LONGITUDINAI^ AN!) Cui^VILINEAR STRAINS . . .387 



XVI CONTENTS. 

PAGE 

EuLES . . .388 

Explanation of Tables of Boiler Pressures on 

FOLLOWING Pages 389 

Table of safe Internal Pressures for Iron Boilers . .390 
Table of safe Internal Pressures for Steel Boilers . . 394 

Marine Boilers 399 

Proportions of Heating Surface to Cylinder and Grate 
Surface of noted Ocean, River, and Ferry-boat 

Steamers 402 

Setting Marine Boilers 404 

Bedding Marine Boilers 405 

Clothing Marine Boilers 405 

Care of Marine Boilers 406 

Repairing Steam-boilers . , . . . . 409 

Tubes . . 410 

Table of Superficial Areas of External Surfaces of 
Tubes of Various Lengths and> Diameters in Square 

Feet 413 

Boiler Flues . . , . . . . . .417 

Table of Squares of Thicknesses of Iron, and Constant 
Numbers to be used in finding the safe External 
Pressure for Boiler Flues . . . . . .419 

Table of safe Working External Pressures on Flues 10 

Feet long . . . ; 420 

Table of safe Working External Pressures on Flues 20 
Feet long . . . . . . . . .422 

Table of Collapsing Pressure of Wrought-iron Boiler- 
flues J Inch thick . . .... . . 425 

Table of Collapsing Pressure of Wrought-iron Boiler- 
flues y5^ Inch thick . . ... . .426 

Table of Collapsing Pressure of Wrought-iron Boiler- 
flues I Inch thick 427 

Table of Collapsing Pressure of Wrought-iron Boiler- 
flues yV Inch thick . 428 

Boiler-heads 429 

Safety- yalves 431 



CONTENTS. XVll 

PAGE 

Table showing the Kise of Safety-valves, in Parts of an 

Inch, at different Pressures 433 

Table of Comparison between Experimental Eesults 

and Theoretical Formulae 435 

KuLES . . . . 437 

Foaming 439 

Incrustation in Steam-boilers . . . . .441 
Internal and External Corrosion of Steam- 
boilers . . 449 

Boiler Explosions 452 

Comparative Strength, of Single -and Double- 
riveted Seams 461 

Calking 464 

Strength of the Stayed and Flat Surfaces . . 468 
Definitions as applied to Boilers and Boiler 

Materials « . 469 

Table deducted from Experiments on Iron Plates for 

Steam-boilers, by the Franklin Institute, Phila. . 470 
Table showing the result of Experiments made on dif- 
ferent Brands of Boiler Iron at the Stevens Institute 

ofTechnology, Hoboken, N. J 471 

Feed- WATER Heaters 472 

Table showing the Units of Heat required to Convert 
One Pound of Water, at the Temperature of 32° Fah., 
into Steam at different Pressures .... 473 

Steam-jackets 474 

Loss OF Pressure in Cylinders induced by Long 

Steam-pipes . . 475 

Priming in Steam-cylinders 476 

Oils and Oiling 477 

Table of Coefficients of Frictions between Plane Sur- 
faces . . 480 

Grate-bars . 482 

Chimneys . 483 

Table showing the proper Diameter and Height of 

Chimney for any kind of Fuel. 484 

2* B 



XVUl CONTENTS. 

PAGE 

Smoke . . , . 485 

Mensuration of the Circle, Cylinder, Sphere, 

ETC 487 

Central and Mechanical Forces and Defini- 
tions . . . . . , . . . . 490 
The Circle 511 

Table containing the Diameters, Circumferences, and 
Areas of Circles, and the Contents of each in 
Gallons, at 1 Foot in Depth. Utility of the 

Table 511 

Logarithms 515 

Table of Logarithms of Numbers from to 1000 . . 516 
Hyperbolic Logarithms . . . . . . 517 

Table of Hyperbolic Logarithms . . . . . 518 

Table containing the Diameters, Circumferences, and 
Areas of Circles from yV of an Inch to 100 Inches, 
advancing by ^^ of an Inch up to 10 Inches, and by 
-J of an Inch from 10 Inches to 100 Inches . . . 521 

Table of Squares, Cubes, and Square and Cube Eoots of 
all Numbers from 1 to 620 532 

Table showing the Tensile Strength of various Qualities 
of Wrought-iron 547 

Table showing the Actual Extension of Wrought-iron 
at various Temperatures 548 

Table showing the Tensile Strength of various Qualities 
of Steel Plates 549 

Table showing the Tensile Strength of various Qualities 
of Cast-iron ' . . . 549 

Table showing the Weight of Boiler-plates 1 Foot 
Square, and from -^ to an Inch thick .... 551 

Table showing the Weight of Square Bar-iron, from -| 
an Inch to 6 Inches Square, 1 Foot Long . . .551 

.Table showing the Weight of Eound-iron from | an 
Inch to 6 Inches Diameter, 1 Foot Long . . . 552 

Table showing the Weight of Cast-iron Balls from 3 to 
13 Inches in Diameter 553 



CONTENTS. XIX 

PAGE 

Table showing the Weight of Cast-iron Plates per Su- 

pa-ficial Feet as per Thickness 553 

Table showing the Weight of Cast-iron Pipes, 1 Foot in 
Length, from J Inch to IJ Inches thick, and from 3 

to 24 Inches Diameter 554 

Table showing the Weight per Square Foot of Wrought- 

iron, Steel, Copper, and Brass 555 

kules for finding the diameter and speed of 

Pulleys 558 

Gearing 559 

Belting . . . . . . . . . .561 

Cement for making Steam-joints and Patching 

Steam-boilers . 568 

Non-conductors for Steam-pipes and Steam-cyl- 
inders . . . . . r . . . 569 

How TO Mark Engineers' or Machinists' Tools , 569 

To Polish Brass . , 570 

Solder ..... 570 

Table showing Weight of different Materials. . . 571 

Joints . 1 571 

Steam-boiler Flue and Tube Cleaners . . . 573 
The Invention and Improvement of the Steam- 
engine . . . . 574 



HAE^D-BOOK 



OP 



LAND AND MAEINE ENGINES. 



THE STEAM-ENGINE 

"VrOTHING furnishes man with greater cause for con- 
Xi gratulation, and even an excusable pride, than the 
feats of that mighty impersonation of brute force and 
human intellect, — the steam-engine, the Hercules of the 
nineteenth century, — which, once launched into the 
world's arena, has gone forth "conquering and to con- 
quer," fulfilling its high destiny as a great civilizing agent, 
with an energy which no human arm can arrest and a 
rapidity which fills us with astonishment and admiration. 
It would be superfluous here to attempt to enumerate 
the benefits which the steam-engine has conferred upon 
mankind. It is a matter of universal knowledge that all 
branches of industry have, since its introduction into use, 
made most important advances through its aid, and every 
day's experience shows it constantly extending its bene- 
ficial influence to new and important purposes, and lending 
its powerful assistance to the further advance of civili- 
zation. 

21 



22 HAND-BOOK OF LAND AND MARINE ENGINES. 

When we consider what the introduction of the steam- 
engine has already done, we have the less difficulty in 
anticipating that this invention may yet be destined to 
achieve objects of whose magnitude and importance we 
can at present form but a faint idea. There are few 
manufacturing processes that have not been revolutionized, 
simplified, and extended during the last fifty years through 
the agency of the steam-engine ; but it is not alone in the 
large manufactory, the splendid steamer, and the rushing 
locomotive, that steam shows its usefulness, but also in our 
villages, cities, and towns, delving into the mines, driving 
the printing-press, helping all trades, and multiplying 
man's power a thousand -fold. Cities have sprung up 
under its magic touch, and on every side we see traces of 
the wonderful efiects produced by this king of motors and 
mighty agent of civilization. 

Then the independence of time, season, circumstance, 
and locality, in consequence of its not being influenced 
by flood, frost, winds, or drought, which mark the great 
superiority of this potent creation of engineering skill, and 
which, in its multiform applications and applicability, 
have invested it with an importance and an interest which 
success seems only to stimulate and render more intense, 
while its complexity of parts and diversity of combination 
offer a wide scope for the exercise of ingenuity, alike highly 
inviting to the theoretical and the practical mechanic. 

Although the civilization of almost every people han 
been more or less affected by the introduction of steam, 
the extent to which steam-power is used is comparatively 
unknown. The total number of steam-engines of all 
descriptions in the world, at the close of eighteen hundred 
and seventy-four, was estimated at two hundred and seven 
thousand six hundred and seventy-seven, representing 
power equal to sixteen million horse-power, which would 



HAND-BOOK OF LAND AND MARINE ENGINES. 23 

be equivalent to the actual power of at least twenty-fJve 
millions of ordinary horses working night and day, or 
equal to the work of two hundred millions of men. Of 
this enormous steam-power the United States had three 
million nine hundred thousand horse-power, and Great 
Britain three million five hundred thousand. But it must 
not be supposed that the utilization of steam-powder in the 
various productive industries of the world is circumscrib- 
ing the area of manual labor or rendering it less remu- 
nerative than formerly; it is quite the reverse, as man 
profits, in some way, by every discovery in science ; and 
though the discovery may compel him to abandon his 
former methods, it will still be found that the material 
results are invariably in his favor. 

The steam-engine, even as a stationary power, is of 
recent origin ; and contemplating the phases which it has 
already -assumed, in connection with the general feeling 
that its energies have not yet been fully developed, it is 
not a matter of wonder that no other object in the entire 
range of human devices has so irresistibly arrogated to 
itself the devotion of the scientist and mechanic. 




24 



HAND-BOOK OF LAND AND MARINE ENGINES. 25 

STEAM. 

Steam is the elastic fluid into which water is converted 
by the- continued application of heat. 

How singular that steam should have been among the 
motive agents of the most ancient idol- worship of Egypt, 
and that it should formerly have been employed with tre- 
mendous effect to delude men and lock them in ignorance, 
while it' now contributes so largely to enlighten and benefit 
mankind ! The instances of the early application of steam 
make us regret that detailed descriptions of the various and 
ingenious devices have not been preserved ; for while we 
condemn the contrivers of such as were used for the purpose 
of delusion, we cannot but admire the ingenuity which they 
displayed in exhibiting before a barbarous people their gods 
in the most imposing manner, and with such terrific efiect. 

The mechanical properties of vapop are similar to those 
of gases in general. The property which is most im- 
portant to be considered, in the case of steam, is the elastic 
pressure. When a vapor or gas is contained in a close 
vessel, the inner surface of the vessel will sustain a press- 
ure arising from the elasticity of the fluid. 

This pressure is produced by the mutual repulsion of 
the particles, which gives them a tendency to fly asunder, 
and causes the mass of the fluid to exert a force tending 
to burst any vessel within which it is confined. This 
pressure is uniformly diffused over every part of the sur- 
face of the vessel in which such a fluid is contained : it is 
to this quality that all the mechanical power of steam 
is due. 

Steam might be said to be the result of a combination 
of water with a certain amount of heat, and the expansive 
force of steam arises from the absence of cohesion between 
and among the particles of water. 
3 



2Q HAND-BOOK OF LAND AND MARINE ENGINES. 

Heat universally expands all matter within its influence, 
whether solid or fluid. But in a solid body it has the co- 
hesion of the particles to overcome ; and this so circum- 
scribes its effect, that in cast-iron, for instance, a rate of 
temperature above the freezing-point sufficient to melt it 
causes an extension of only about one-eighth of an inch 
in a foot. With water, however, a temperature of 212"^, 
or 180"^ above the freezing-point (and which is far from a 
red heat), converts it into steam of 1700 times its original 
bulk or volume. 

Steam cannot mix with air while its pressure exceeds 
that of the atmosphere ; and it is this property, with that 
which makes the condition of a body dependent on its 
temperature, that explains the condensing property of 
steam. 

In a cylinder once filled with steam of a pressure of 15 
pounds or more to the square inch, all air is excluded ; 
now, as the existence of the steam depends on its temper- 
ature, by abstracting that temperature (which may be 
done by immersing the cylinder in cold water or cold air), 
the contained steam assumes the state due to the reduced 
temperature, and this state will be water. 

The latent op concealed heat of steam is one of the 
most noteworthy properties. The latent heat of steam, 
though showing no eflTect on the thermometer, may be as 
easily known as the sensible or perceivable heat. 

To show this property of steam by experiment, place an 
indefinite amount of water in a closed vessel, and let a 
pipe, proceeding from its upper part, communicate with 
another vessel, which should be open, and, for convenience 
of illustration, shall contain just 6i pounds of water at 
32°, or just freezing. The pipe from the closed vessel 
must reach nearly to the bottom of the open one. By 
boiling the water contained in the first vessel until steam 



H AMD-BOOK OF LAND AND MARINE ENGINES. 27 

enough has passed through the pipe to raise the water in 
the open vessel to the boiling-point (212° Fah.), we shall 
find the weight of the water contained by the latter to be 
6? pounds. Now, this addition of one pound to its weight 
has resulted solely from the admission of steam to it ; and 
this pound of steam, therefore, retaining its own tempera- 
ture of 212^, has raised di pounds of water 180°, or an 
equivalent to 990°, and, including its own temperature, we 
have 1201°, which it must have possessed at first. 

The sum of the latent and sensible heat of steam is in all 
cases nearly constant, and does not vary much from 1200°. 

The elasticity of steam increases with an increase in 
the temperature applied, but not in the same ratio. If 
steam is generated from water at a, temperature which 
gives it the same pressure as the atmosphere, an additional 
temperature of 38° will give it the pressure of two atmos- 
pheres ; a still further addition of 42° gives it the tension 
of four atmospheres ; and with each successive addition of 
temperature of between 40° and 50° the pressure becomes 
doubled. 

An established relation must exist between the temper- 
ature and elasticity of steam ; in other words, water at 
212° Fah. must be under the pressure of the steam natu- 
rally resulting from that temperature, and so at any other 
temperature. 

If this natural pressure on the surface of the water be 
removed without a corresponding reduction in the temper- 
ature, a violent ebullition of the water is the immediate 
result. 

Another result attending formation of steam is, that 
when an engine is in operation and working ofi* a proper 
supply of steam, the water level in the boiler artificially 
rises, and shows by the gauge-cocks a supply greater than 
that which really exists. 



28 HAND-BOOK OF LAND AND MARINE ENGINES. 

As the pressure of steam is increased, the sensible 
heat is augmented, and the latent heat undergoes a cor- 
responding diminution, and vice versa. The sum of the 
sensible and latent heat is, in fact, a constant quantity ; 
the one being always increased at the expense of the 
other. 

It has been shown that in converting water at 32° of 
temperature, and under a pressure of 15 pounds per square 
inch, it was necessary iBrst to give it 180^ additional sen- 
sible heat, and afterwards 990° of latent heat, the total 
heat imparted to it being 1170°. Such, then, is the actual 
quantity of heat which must be imparted to ice-cold water 
to convert it into steam. The actual temperature to which 
water would be raised by the heat necessary to evaporate 
it, if its evaporation could be prevented by confining it in 
a close vessel, will be found by adding 82° to 1170°. 

It may, therefore, be stated that the heat necessary for 
the evaporation of ice-cold water is as much as would 
raise it to the temperature of 1202°, if its evaporation 
were prevented. 

If the temperature of red-hot iron be, as it is supposed, 
800° or 900°, and that all bodies become incandescent at 
the same temperature, it follows that to evaporate water it 
is necessary to impart to it 400° more heat than would be 
sufficient to render it red-hot, if its evaporation were pre- 
vented. 

It has been asserted, in some scientific works, that by 
mere mechanical compression, steam will be converted 
into water. This is, however, an error ; since steam, in 
whatever state it may exist, must possess at least 212° of 
heat ; and as this quantity of heat is sufficient to maintain 
it in the vaporous form under whatever pressure it may 
be placed, it is clear that no compression or increase of 
pressure can diminish the actual quantity of heat con- 



HAND-BOOK OF LAND AND MARINE ENGINES. 29 

tained in the steam, and it cannot, therefore, convert any 
portion of the steam into power. 

Steam, by mechanical pressure, if forced into a dimin- 
ished volume, will undergo an augmentation both of tem- 
perature and pressure, the increase of temperature being 
greater than the diminution of volume; in fact, any 
change of volume which it undergoes will be attended 
with the change of temperature and pressure indicated in 
the table on pages 39-43. 

The steam, after its volume has been changed, will as- 
sume exactly the pressure and temperature which it would 
have in the same volume if it were immediately evolved 
from water. 

Let us suppose a cubic inch of water converted into 
steam under a pressure of 15 pounds per square inch, and 
the temperature of 212°. Then let its volume be reduced 
by compression in the proportion of 1700 to 930. When 
so reduced, its pressure will be found to have risen from 
15 pounds per square inch to 29 J pounds per square inch ; 
but this is exactly the state as to pressure, temperature, 
and density the steam would be in if it were immediately 
raised from water under the pressure of 29 J pounds per 
square inch. It appears, therefore, that in whatever man- 
ner, after evaporation, the density of steam be changed, 
whether by expansion or contraction, it will still remain 
the same as if it were immediately raided from water in 
its actual state. 

The circumstance which has given rise to the erroneous 
notion that mere mechanical compression will produce a 
condensation of steam, is that the vessel in which steam 
is contained must necessarily have the same temperature 
as the steam itself. 

Water while passing into steam suffers a great enlarge- 
ment of volume ; steam, on the other hand, in being con- 
3* 



80 HAND-BOOK OF LAND AND MARINE ENGINES. 

verted into water, undergoes a corresponding diminution 
of volume. It has been seen that a cubic inch of water, 
evaporated at the temperature of 212°, swells into 1700 
cubic inches of steam. It follows, therefore, that if a 
closed vessel, containing 1700 cubic inches of steam, be 
exposed to cold sufficient to take from the steam all its 
latent heat, the steam will be reconverted into water, and 
will shrink into its original dimensions, and will leave the 
remainder of the vessel a vacuum. 

This property of steam has supplied the means, in 
practical mechanics, of obtaining that amount of me- 
chanical power which the properties of the atmosphere 
confer upon a vacuum. 

The temperature and pressure of steam produced by 
immediate evaporation, when it has received no heat save 
that which it takes from the water, have a fixed relation 
one to the other. 

If this relation was known and expressed by a mathe- 
matical formula, the temperature might always be inferred 
from the pressure, and vice versa. 

But physical science has not yet supplied any principle 
by which such a formula can be deduced from any known 
properties of liquids. 

The same difficulty which attends the establishment of 
a general formula expressing the relation between the 
temperatures and pressures of steam, also attends the de- 
termination of one expressing the relation between the 
pressure and augmented volume into which water expands 
by evaporation. 

In the preceding observations, steam has been considered 
as receiving no heat except that which it takes from the 
water during the process of evaporation ; the amount of 
heat of which, as has been shown, is 1170° more than the 
heat contained in ice-cold 'water. But steam, after having 



HAND-BOOK OF LAND AND MARINE ENGINES. 31 

been formed from water by evaporation, may, like all other 
material substances, receive an accession of heat from any 
external source, and its temperature may therefore be ele- 
vated. 

If the steam to which such additional heat is imparted 
be so confined as to be incapable of enlarging its dimen- 
sions, the effect produced upon it by the increase of tem- 
perature will be an increase of pressure. 

But if, on the other hand, it be confined under a given 
pressure, with power to enlarge its volume, subject to the 
preservation of that pressure, as would be the case if it 
were contained in a cylinder under a movable piston 
loiaded with a given pressure, then the effect of the aug- 
mented temperature will be, not an increase of pressure, 
but an increase of volume ; and the increase of volume, 
in this latter case, will be in exactly the same proportion 
as the increase of pressure in the former case. 

These effects of elevated temperature are common, not 
only to the vapors of all liquids, but also to all permanent 
gases ; but, what i^ much more remarkable, the numerical 
amount of the augmentation of pressure or volume pro- 
duced by a given increase of temperature is the same for 
all vapors and gases. If the pi-essure which any gas or 
' vapor would have, were it reduced to the temperature of 
melting ice, be expressed by 100,000, the pressure which 
it will receive for every degree of temperature by which 
it is raised will be expressed by 208 J, or what amounts to 
the same, the additional pressure produced by each degree 
of temperature will be the 480th part of its pressure at the 
temperature of melting ice. 

Steam which thus receives additional heat after its 
separation from the water from which it is evolved has 
been called superheated steam, to distinguish it from common 
steam, which is that usually employed in steam-engines. 



\ 



82 



HAND-BOOK OF LAND AND MARINE ENGINES. 



Steam of atmospheric pressure occupies 1669 times the 
volume of the water from which it is raised, and as a cubic 
foot of water weighs 62*4 pounds, a cubic foot of steam 
of atmospheric pressure weighs about '038 pound. In 
order to exert a pressure by its mere dead weight of 14*7 
pounds per square inch, such steam of uniform density 
would have to stand at a height of 10 J miles — ^the velocity 
due to a fall from this height in 1888 feet per second, and 
this, accordingly, is the velocity with which steam of at- 
mospheric pressure enters a vacuum. And if the velocity 
of steam were inversely as its pressure, this would be the 
velocity of steam of every pressure in moving into a 
vacuum, since, so far as generating effluent velocity is 
concerned, the mere elasticity of a gas is inoperative. 

The effluent velocity of steam into the atmosphere or 
into steam of lower pressure, then, has to be carefully con- 
sidered in the treatment of steam-engines. In the follow- 
ing table, the pressure given in pounds above the atmos- 
phere is 0*3 pound less than the pressure employed in 
making the calculation : 



Pressure above 


Velocity of Escape 


Pressure above 


Velocity of Escape 


the Atmosphere. 


per Second. ^ 


the Atmosphere. 


per Second. 


Pounds. 


Feet. 


Pounds. 


Feet. 


1 


540 


50 


1,736 


2 


698 


60 


1,777 


3 


814 


70 


1,810 


4 


905 


80 


1,835 


5 


981 


90 


1,857 


10 


1,232 


100 


1,875 


20 


1,476 


110 


1,889 


30 


1,601 


120 


1,900 


40 


1,681 


130 


1,909 



To saturated steam, or steam as it rises from the water 



HAND-BOOK OF LAND AND MARINE ENGINES. 83 

from which it is generated, these calculations of course 
only apply. Whatever may be the pressure per square inch 
common to different conditions of steam, the effluent 
velocity will be inversely as the square root of the specific 
gravity of steam. If the steam be superheated, its specific 
gravity for a given pressure will be diminished, and its 
velocity of escape into the air or into a vacuum will be in- 
creased. If, on the contrary, the steam carry with it any 
suspended moisture, its specific gravity for a given press- 
ure will be increased and its velocity of escape diminished. 

A very important question will probably arise in the 
mind of the reader as to the amount of work that a given 
weight of steam is capable of performing. A pound of 
steam, of say 120 pounds pressure above that of the atmos- 
phere, is virtually a pound of water heated 1681 degrees 
above the absolute zero of a perfect gas thermometer, 1220° 
above Fahrenheit's zero, 1188 degrees above the freezing- 
point, or 1118° above the sensible temperature of steam 
of one pound absolute pressure per square inch, the lowest 
pressure at which a condensing-engine could be expected 
to work. Either of these total temperatures, multiplied 
by 772, will give the energy in foot-pounds theoretically 
due to the steam when worked down, say, into water of 
the corresponding temperature. 

But it must be remembered that, as a gas (to which 
steam in this case is necessarily compared) it would, upon 
the accepted law of expansion, only lose its elasticity at a 
temperature below the freezing-point. If we work down 
to 102°, the temperature of water from which steam of 
one pound total pressure would escape, w^e shall have an 
energy, for one pound weight of steam, of 863,096 foot- 
pounds ; and if 10 pounds of steam be evaporated from 
102° by one pound of coal, giving'^ 8,630,960 foot-pounds 
per pound of coal, an engine working up to the full 

C 



34 HAND-BOOK OF LAND AND MARINE ENGINES. 

power of the steam would require but |||§f g^ = 0*23 
pound, or less than four oxtnces of coal per indicated horse- 
power per hour, an hourly horse-power being 33,000 X 60 
= 1,980,000 foot-pounds. 

To obtain such a result, the steam must in the very act 
of doing work be reduced to one pound of water at 102"^. 
This, however, is quite a theoretical deduction, and noth- 
ing like it could, with our present knowledge, be approached 
in practice ; especially, as in expanding, the steam is con- 
stantly losing heat and liquefying in the very act of doing 
work, and thus losing pressure apart from the loss due to 
the apparent enlargement of volume. 

Superheated steam admits of losing a part of its heat 
without suffering partial condensation ; but common steam 
is always partially condensed, if any portion of heat be 
withdrawn from it. But it must be remembered, any 
additional arrangements for heating the steam can but 
complicate the machinery, and thus require increase of 
space, besides adding to the cost of the engine. But these 
objections are more serious in the case of the marine engine, 
the boilers of which are mostly fed with sea-water, strongly 
impregnated with various salts, and particularly with 
chloride of sodium. At the usual temperature of the 
steam used for working these engines, which is generally 
from 250° to 270°, the presence of this salt causes no in- 
convenience ; but when the steam is superheated, chemical 
decomposition ensues, and the chlorine thus set free attacks 
all the brass work of the engine with which it comes in 
contact, and the valves and valve-seats are speedily de- 
stroyed and the engine put out of order. 

But there can be no doubt whatever but that the use 
of superheated steam is more economical than that of 
ordinary saturated steam. In some of the scientific reports 
on this subject, it has been shown that there is a saving of 



HAKD-BOOK OF LAND AND MARINE ENGINES. 60 

from 20 to 25 per cent, in the fuel consumed. This fact 
has induced inventors to turn their attention to the task 
of devising some practical appliances for producing steam 
in this superheated condition. 

Motion of Steam. — Steam, if unimpeded, moves with 
great velocity from one enclosure to another, under very- 
slight differences of pressure. The laws which regulate 
this movement, though apparently of a simple character, 
are not so easily reduced to exact formula as would seem 
desirable. All the rules, therefore, which are given, must 
be taken with due reserve and with important qualifica- 
tions. The conditions of the free motion of steam will be 
exhibited as nearly as science has been able to estimate them. 

These conditions are three: Steam may flow into a 
vacuum, or into the atmosphere, or into steam of less 
density. The conditions of its flow in all these cases 
are of course entirely different. In the middle case — 
that of its flow into the atmosphere — about 15 pounds 
of its total pressure go for nothing, being expended in 
overcoming the atmospheric resistance, and before the 
slightest motion of its own or impulse to any other body 
is possible. The law applicable to non-elastic fluids is the 
same as that which applies to gases and steam. 

Volume and Weight of Steam. — Seventy-five cubic feet 
of steam at a pressure of 140 pounds per square inch 
weigh 26 pounds. 

Five cubic feet of steam at a pressure of 75 pounds per 
square inch weigh 1 pound. 

One cubic foot of steam at a pressure of 15 pounds per 
square inch weighs .038 pound. 

Steam, at any given pressure, always stands at a certain 
temperature, which is termed the " temperature due to the 
pressure." Steam follows very nearly the same law that 
all other gaseous bodies are subject to in acquiring ad- 



36 HAND-BOOK OF LAND AND MARINE ENGINES. 

ditional degrees of heat. The law is, briefly, as follows : 
That all gaseous bodies expand equally for equal additions 
of temperature ; and that the progressive rate of expan- 
sion is equal for equal increments of temperature. 

If two volumes of steam of the same weight be com- 
pared, we institute a comparison between their relative 
volumes; for, being of the same weight, they are pro- 
duced from the same quantity of water. The relative 
volume of steam being the absolute volume divided by 
the volume of water from which it was produced,. the ratio 
of any two relative volumes of steam is the same as the 
ratio of their absolute volumes. So also with steam held 
in contact with the water in the boiler, the same pressure 
exhibited by the gauge corresponds to the same temper- 
ature in the boiler, and the same temperature in the boiler 
will always give the same corresponding pressure of steam. 
Therefore, if we increase the temperature, we increase the 
pressure and density, and we, of course, get the greatest 
pressure and density that steam can have at that temper- 
ature. 

The table on page 39 shows that the saving of fuel is in 
proportion to the increase of pressure — the advantage of 
generating and using high-pressure steam is thereby made 
apparent. The table also shows that the last 10 pounds 
of additional pressure only require four degrees of heat 
to raise it ; whereas, the first 10 pounds of pressure above 
the atmosphere require 29 additional degrees of heat to 
raise it — a difference of 25 degrees. 

It also shows that at 212^ the total heat of steam is 
11784°, which gives a difference of 966*1°. This heat, 
usually termed latent, is absorbed in performing the work 
of expanding the particles of water from the solid to the 
gaseous state. Now, suppose the water is evaporated at 
60 pounds pressure, the steam will have a temperature of 
307°, and a total heat of 1207°. If the feed has been 



HAND-BOOK OF LAND AND MARINE ENGINES. 



37 




38 HAND-BOOK OF LAND AND MARINE ENGINES. 

introduced at 60°, it is evident that 1147° of heat have 
been imparted. 

As the amount evaporated is inversely proportional to 
the quantity of heat required, we have 1147 -i- 966 = 1*2. 
Multiplying by this factor, the quantity evaporated at 60 
pounds pressure from 60°, we obtain the amount that would 
be evaporated at 212° by the same quantity of fuel. 

By the same table will be seen the comparatively small 
increase of heat required to evaporate water at higher 
pressures. Suppose we take water evaporated at 45 pounds 
pressure from a feed temperature of 60°, then each pound 
of water will require 1202*7° — 60 = 1142*7° for its 
conversion into steam. 

If we take the pressure at 100 pounds, we shall have 
1216*5 — 60 = 1156-5° as the quantity required. The 
difference between these two total quantities is only 13*8°, 
and is so small as to be scarcely worth considering. 
Leaving out of account the loss due to the slight reduc- 
tion of the conducting power of the material, the increased 
amount of heat required for the higher pressure will be 
only ^^^ of the total heat required at 60 pounds. The 
economy of using steam of a high pressure is clearly 
manifest when, at the same time, advantage is taken of the 
facilities it offers for working expansively in the cylinder. 

Theory has long since demonstrated the economical ad- 
vantages to be derived from the use of high steam press- 
ures combined with high grades of expansion in the 
cylinder. The practical difficulties that stood in the way 
having been gradually and successfully overcome, the re- 
sult has been the marked changes from the 7 pound and 
10 pound pressures, so common forty years ago, to the 
pressures of from 80 pounds to 100 pounds, at present 
employed ; and the more general employment of the higher 
pressures will be demanded as the advantages of using 
steam expansively become more generally recognized. 



II 



HAND-BOOK OF LAND AND MARINE ENGINES. 



39 



TABLE 

SHOWING THE TEMPERATURE AND WEIGHT OF STEAM AT DIF- 
FERENT PRESSURES FROM 1 POUND PER SQUARE INCH TO 300 
POUNDS, AND THE QUANTITY OF STEAM PRODUCED FROM 1 
CUBIC INCH OF WATER, ACCORDING TO PRESSURE. 



al pressure 
square inch 

isured from a 
vacuum. 


II 
ll 


sible temper- 
re in Fahren- 
3it degrees. 


III 




ative volume 
steam com- 
ed with wa- 
from which 
was raised. 


Ill 




II" . 







i-oir- 


1 




102.1 


1144.5 


.0030 


20582 


2 




126.3 


1151.7 


.0058 


10721 


3 




141.6 


1156.6 


.0085 


7322 


4 




153.1 


1160.1 


.0112 


5583 


5 




162.3 


1162.9 


.0138 


4527 


6 




170.2 


1165.3 


.0163 


3813 


7 




176.9 


1167.3 


.0189 


3298 


8 




182.9 


1169.2 


.0214 


2909 


9 




188.3 


1170.8 


.0239 


2604 


10 




193.3 


1172.3 


.0264 


2358 


11 




197.8 


1173.7 


.0289 


2157 


12 




202.0 . 


1175.0 


.0314 


1986 


13 




205.9 


1176.2 


.0338 


1842 


14 




209.6 


1177.3 


.0362 


1720 


14.7 


*"*0 


212.0 


1178.1 


.0380 


1642 


15 


.3 


213.1 


1178.4 


.0387 


1610 


16 


1.3 


216.3 


1179.4 


.0411 


1515 


17 


2.3 


219.6 


1180.3 


.0435 


1431 


18 


3.3 


222.4 


1181.2 


.0459 


1357 


19 


4.3 


225.3 


1182.1 


.0483 


1290 


20 


5.3 


228.0 


1182.9 


.0507 


1229 


21 


6.3 


230.6 


1183.7 


.0531 


1174 


22 


7.3 


233.1 


1184.5 


.0555 


1123 


23 


• 8.3 


235.5 


1185.2 


.0580 


1075 


24 


9.3 


237.8 


1185.9 


.0601 


1036 


25 


10.3 


240.1 


1186.6 


.0625 


996 


26 


11.3 


242.3 


1187.3 


.0650 


958 


27 


12.3 


244.4 


1187.8 


.0673 


926 


28 


13.3 


246.4 


1188.4 


.0696 


895 


29 


14.3 


248.4 


1189.1 


.0719 


866 


30 


15.3 


250.4 


1189.8 


.0743 


838 


31 


16.3 


252.2 


1190.4 


.0766 


813 



40 



HAND-BOOK OF LAND AND MARINE ENGINES. 



TABLE— ( Qontinued) . 



Total pressure 

per square inch 

measured from a 

vacuum. 


1 • 

• if 


Sensible temper- 
ature in Fahren- 
heit degrees. 


m 
ill 




Relative volume 
of steam com- 
pared with wa- 
ter from which 
it was raised. 


32 


17.3 


254.1 


1190.9 


.0789 


789 


33 


18.3 


255.9 


1191.5 


.0812 


767 


34 


19.3 


257.6 


1192.0 


.0835 


746 


35 


20.3 


259.3 


1192.5 


.0858 


726 


36 


21.3 


260.9 


1193.0 


.0881 


707 


37 


22.3 


262.6 


1193.5 


.0905 


688 


38 


23.3 


264.2 


1194.0 


.0929 


671 


39 


24.3 


265.8 


1194.5 


.0952 


655 


40 


25.3 


267.3 


1194.9 


.0974 


640 


41 


26.3 


268.7 


1195.4 


.0996 


625 


42 


27.3 


270.2 


1195.8 


.1020 


611 


43 


28.3 


271.6 


1196.2 


.1042 


598 


44 


29.3 


273.0 


1196.6 


.1065 


595 


45 


30.3 


274.4 


1197.1 


.1089 


572 


46 


31.3 


275.8 


1197.5 


.1111 


561 


47 


32.3 


277.1 


1197.9 


.1133 


550 


48 


33.3 


278.4 


1198.3 


.1156 


539 


49 


34.3 


279.7 


1198.7 


.1179 


529 


50 


35.3 


281.0 


1199.1 


.1202 


518 


51 


36.3 


282.3 


1199.5 


.1224 


509 


52 


37.3 


283.5 


1199.9 


.1246 


500 


53 


38.3 


284.7 


1200.3 


.1269 


491 


54 


39.3 


285.9 


1200.6 


.1291 


482 


55 


40.3 


287.1 


1201.0 


.1314 


474 


56 


41.3 


288.2 


1201.3 


.1336 


466 


57 


42.3 


289.3 


1201.7 


.1364 


458 


58 


43.3 


290.4 


1202.0 


.1380 


451 


59 


44.3 


291.6 


1202.4 


.1403 


444 


60 


45.3 


292.7 


1202.7 


.1425 


437 


61 


46.3 


293.8 


1203.1 


.1447 


430 


62 


47.3 


294.8 


1203.4 


.1469 


424 


63 


48.3 


295.9 


1203.7 


.1493 


417 


64 


49.3 


296.9 


1204.0 


.1516 


411 


65 


50.3 


298.0 


1204.3 


.1538 


405 


66 


51.3 


299.0 


1204.6 


.1560 


399 


67 


52.3 


300.0 


1204.9 


.1583 


393 


6S 


53.3 


300.9 


1205.2 


.1605 


388 


69 


54.3 


301.9 


1205.5 


.1627 


383 



HAND-BOOK OF LAND AND MARINE ENGINES. 



41 



TABLE--( Continued). 



al pressure 
square inch 
isured from a 
vacuum. 


Is 


sible temper- 
re in Fahren- 
eit degrees. 


ill 
ill 


go 


ative volume 
steam corn- 
ed with wa- 
from which 
was raised. 




g"c3 




el's 





o , is f"^ 


70 


55.3 


302.9 


1205.8 


.1648 


378 


71 


56.3 


303.9 


1206.1 


.1670 


373 


72 


57.3 


304.8 


1206.3 


.1692 


368 


73 


58.3 


305.7 


1206.6 


.1714 


363 


74 


59.3 


306.6 


1206.9 


.1736 


359 


75 


60.3 


307.5 


1207.2 


.1759 


m 


76 


61.3 


308.4 


1207.4 


.1782 


349 


77 


62.3 


309.3 


1207.7 


.1804 


345 


78 


63.3 


310.2 


1208.0 


.1826 


341 


79 


64.3 


311.1 


1208.3 


.1848 


337 


80 


65.3 


312.0 


1208.5 


.1869 


333 


81 


66.3 


312.8 


1208.8 


.1891 


329 


82 


67.3 


313.6 


1209.1 


.1913 


325 


83 


68.3 


314.5 


1209.4 


.1935 


321 


84 


69.3 


315.3 


1209.6 


.1957 


318 


85 


70.3 


316.1 


1209.9 


.1980 


314 


86 


71.3 


316.9 


1210.1 


.2002 


311 


S7 


72.3 


317.8 


1210.4 


.2024 


308 


88 


73.3 


318.6 


1210.6 


.2044 


305 


89 


74.3 


319.4 


1210.9 


.2067 


301 


90 


75.3 


320.2 


1211.1 


.2089 


298 


91 


76.3 


321.0 


1211.3 


.2111 


295 


92 


77.3 


321.7 


1211.5 


.2133 


292 


93 


78.3 


322.5 


1211.8 


,2155 


289 


94 


79.3 


323.3 


1212.0 


.2176 


286 


95 


80.3 


324.1 


1212.3 


.2198 


283 


96 


81.3 


324.8 


1212.5 


.2219 


281 


97 


82.3 


825.6 


1212.8 


.2241 


278 


98 


83.3 


326.3 


1213.0 


.2263 


275 


99 


84.3 


327.1 


1218.2 


.2285 


272 


100 


85.3 


327.9 


1213.4 


.2307 


270 


101 


86.3 


328.5 


1213.6 


.2329 


267 


102 


87.3 


329.1 


1213.8 


.2351 


265 


103 


88.3 


329.9 


1214.0 


.2373 


262 


104 


89.3 


330.6 


1214.2 


.2393 


260 


105 


90.3 


331.3 


1214.4 


.2414 


257 


106 


91.3 


331.9 


1214.6 


.2435 


255 


107 


92.3 


332.6 


1214.8 


.2456 


253 



4* 



42 



HAND-BOOK OF LAND AND MARINE ENGINES, 



TABLE— (Continued). 



al pressure 
square inch 

isured from a 
vacuum. 


03 

Si 

,d 
2f 


sible temper- 
re in Fahren- 
eit degrees. 


d^l 


0) 


ative volume 
steam com- 
ed with wa- 
from which 
was raised. 




£ 


ir 


e|o 


'S d 


w'sl^" 


108 


93.3 


333.3 


1215.0 


.2477 


251 


109 


94.3 


334.0 


1215.3 


.2499 


249 


110 


95.3 


334.6 


1215.5 


.2521 


247 


111 


96.3 


335.3 


1215.7 


.2543 


245 


112 


97.3 


336.0 


1215.9 


.2564 


243 


113 


98.3 


336.7 


1216.1 


.2586 


241 


114 


99.3 


337.4 


1216.3 


.2607 


239 


115 


100.3 


338.0 


1216.5 


.2628 


237 


116 


101.3 


338.6 


1216.7 


.2649 


235 


117 


102.3 


339.3 


1216.9 


.2674 


233 


118 


103.3 


339.9 


1217.1 


.2696 


231 


119 


104.3 


340.5 


1217.3 


.2738 


229 


120 


105.3 


341.1 


1217.4 


.2759 


227 


121 


106.3 


341.8 


1217.6 


.2780 


225 


122 


107.3 


342.4 


1217.8 


.2801 


224 


123 


108.3 


343.0 


1218.0 


.2822 


222 


124 


109.3 


343.6 


1218.2 


.2845 


221 


125 


110.3 


344.2 


1218.4 


.2867 


219 


126 


111.3 


344.8 


1218.6 


.2889 


217 


127 


112.3 


345.4 


1218.8 


.2911 


215 


128 


113.3 


346.0 


1218.9 


.2933 


214 


129 


114.3 


346.6 


1219.1 


.2955 


212 


130 


115.3 


347.2 


1219.3 


.2977 


211 


131 


116.3 


347.8 


1219.5 


.2999 


209 


132 


117.3 


348.3 


1219.6 


.3020 


208 


133 


118.3 


348.9 


1219.8 


.3040 


206 


134 


119.3 


349.5 


1220.0 


.3060 


205 


135 


120.3 


350.1 


1220.2 


.3080 


203 


136 


121.3 


350.6 


1220.3 


.3101 


202 


137 


122.3 


351.2 


1220.5 


.3121 


200 


138 


123.3 


351.8 


1220.7 


.3142 


199 


139 


124.3 


352.4 


1220.9 


.3162 


198 


140 


125.3 


352.9 


1221.0 


.3184 


197 


141 


126.3 


353.5 


1221.2 


.3206 


195 


142 


127.3 


354.0 


1221.4 


.3228 


194 


143 


128.3 


354.5 


1221.6 


.3258 


193 


144 


129.3 


355.0 


1221.7 


.3273 


192 


145 


130.3 


355.6 


1221.9 


.3294 


190 



HAND-BOOK OF LAND AND MARINE ENGINES. 



43 



TABLE— ( Concluded). 



Total pressure 

per square inch 

measured from a 

vacuum. 


1^ 


Sensible temper- 
ature in Fahren- 
heit degrees. 




o ^ 


Relative volume 
of steam com- 
pared with wa- 
ter from which 
it was raised. 


146 


131.3 


356.1 


1222.0 


.3315 


189 • 


147 


132.3 


356.7 


1222.2 


.3336 


188 


148 


133.3 


357.2 


1222.3 


.3357 


187 


149 


134.3 


357.8 


1222.5 


.3377 


186 


150 


135.3 


358.3 


1222.7 


.3397 


184 


155 


140.3 


361.0 


1223.5 


.3500 


179 


160 


145.3 


363.4 


1224.2 


.3607 


174 


165 


150.3 


366.0 


1224.9 


.3714 


169 


170 


155.3 


368.2 


1225.7 


.3821 


164 


175 


160.3 


370.8 


1226.4 


.3928 


159 


180 


165.3 


372.9 


1227.1 


.4035 


155 


185 


170.3 


375.3 


1227.8 


.4142 


151 


190 


175.3 


377.5 


1228.5 


.4250 


148 


195 


180.3 


379.7 


1229.2 


.4357 


144 


200 


185.3 


381.7 


1229.8 


.4464 


141 


210 


195.3 


386.0 


1231.1 


.4668 


135 


220 


205.3 


389.9 


1232.8 


.4872 


129 


230 


215.3 


393.8 


1233.5 


.5072 


123 


240 


225.3 


397.5 


1234.6 


.5270 


119 


250 


235.3 


401.1 


1235.7 


.5471 


114 


260 


245.3 


404.5 


1236.8 


.5670 


110 


270 


255.3 


407.9 


1237.8 


.5871 


106 


280 


265.3 


411.2 


1238.8 


.6070 


102 


290 


275.3 


414.4 


1239.8 


.6268 


99 


300 


285.3 


417.5 


1240.7 


.6469 


96 



WORKING STEAM EXPANSIVELY. 

There are two modes of applying the power of steam 

to the working cylinders of steam-engines, namely : One, 
allowing steam to flow from the boiler during the whole 
length of the stroke ; and the other, cutting it off from 
the boiler when the piston has travelled a determined 
distance — the great and paramount object of this last 
arrangement being a saving of fuel. 



44 . HAND-BOOK OF LAND AND MARINE ENGINES. 

If steam be applied the full length of the stroke, the 
average pressure will be as the pressure per square inch 
upon the piston; but if the steam be cut off at half 
stroke, — suppose the pressure to be 65 pounds per inch 
when the pressure of the atmosphere is added, — there 
will be a mean equivalent, or average pressure, through- 
out the stroke of 55 pounds per square inch, being only 
10 pounds less than the full pressure, or 16 per cent, of a 
loss in power, though half the former quantity of steam 
has only been used. This alone effects a saving of 34 per 
cent, in fuel, and shows the great benefit to be derived 
from expansion in one cylinder. 

If this principle be true, and its truth is undeniable, it 
is quite evident that the greatest economy will result from 
extending to their full limit the cylinders of steam-engines, 
and making them of sufficient capacity for this purpose ; 
though with the high-pressures, with which expansion is 
most available, they will require to be less than are usually 
made, to allow the engines to produce the maximum effect. 

The expansive property of steam is strictly mechani- 
cal, and is a property common to all fluids — air, gas, etc. 
It simply consists in this — that vapor of a given elastic 
force will expand to certain limits, and during the process 
of expansion will act on opposing bodies with a force 
gradually decreasing, causing a diminution of elastic 
power in an inverse ratio of the increase of volume, until 
it has reached the limits of its power, or is counterbalanced 
by the resistance of a surrounding medium. Thus, steam 
of any given pressure, expanded to twice its original bulk, 
will exert only one-half its original power. 

If a partial vacuum be formed on one side of a piston, 
its motion will be continued until the density of the steam 
on the other side be as low as that of the uncondensed 
vapor on the vacuum side of the piston. It is clear that 



HAND-BOOK OF LAND AND MARINE ENGINES. 45 

the power which may be obtained by thus impelling a 
piston will be the average between the highest and the 
lowest pressure upon the piston. It must also be under- 
stood that it is a saving^ and not a gain, that thus results 
from expansion ; a power being made available which was 
before lost, by using the steam up to its last impelling 
force, and not allowing it to escape until the whole of that 
available force has been expended. 

This accounts for some engines using more fuel and 
steam than others, because the steam is not expanded to 
its utmost limit, in consequence of the steam not being 
cut off by the valve soon enough, or that the load on the 
engine is great, and requires the steam to be longer on the 
piston before it is cut off. If the load on the engine be 
such as to allow the steam to be cut off early, and to 
expand to its full available limits in the cylinder, then 
the most will have been made of it ; the highest pressure 
in the boiler will have been used upon the piston and 
down to the lowest point. 

Were atmospheric air compressed so as to exert a force 
of 20 pounds on the square inch, and were the supply to 
be continued throughout the stroke, an impulse would be 
given to the piston equal to 20 pounds to the square inch 
during the whole stroke ; but if the air was allowed to 
expand, the impulse would only be as the average, or 10 
pounds. It will be evident that, if in the former case the 
air was suffered to depart from the cylinder at the same 
elasticity as that which it entered, we should lose the force 
which was necessary to compress it to its density ; while, 
by expanding it to its limits, we apply every part of that 
force. 

The main-spring of a watch actuates its machinery in 
this manner : an increasing effort is required to wind up 
the spring, and a decreasing impulse is given back to the 



46 HAND-BOOK OF LAND AND MARINE ENGINES. 

machinery. But if, after the spring had partially un- 
coiled itself, it were then liberated, the force which wound 
it up to its last impelling point would be totally lost. 

So in the steam-engine ; if the steam be allowed to escape 
from the cylinder before its force is expanded to the lowest 
available pressure, the loss will be in proportion to the 
amount of the pressure not made available. 

A certain quantity of fuel is required to raise steam to 
a certain elasticity. If that steam be allowed, after hav- 
ing moved the piston, to escape into the atmosphere or 
condenser without having acted expansively, a portion of 
the fuel which was consumed to raise the steam up to that 
point of elasticity will have been lost. In one case, a 
given bulk of fuel would produce fifty ; in the other case, 
it would produce fifty, added to all the intermediates 
down to the lowest expansive force. 

By this it will be apparent that the advantages arising 
from expansion increase with the density of the steam. 
In round numbers, 65 pounds of high-pressure steam will 
perform more than seven times the duty of 25 pounds of 
low-pressure steam ; a fact greatly in favor of high-pressure 
steam and expansion. 

Expansion is, perhaps, the most extraordinary property 
of steam. The merit of the discovery is due to Horn- 
blower, who, in 1781, obtained a patent for the invention. 

The principle of expanding the steam in the condensing 
engine is the same as in the non-condensing engine, ex- 
cepting that the steam which exhausts into the atmosphere 
cannot expand below 15 pounds per square inch, because 
the exhaust is open to the pressure of the atmosphere in 
all cases. The resistance of the atmosphere (15 pounds) 
must be added to the pressure of steam above atmospheric 
pressure, when calculating the pressure of the expansion 
of steam upon the piston. 



HAND-BOOK OF LAND AND MARINE ENGINES. 47 

Example. — Steam at 20 pounds pressure above the 
atmosphere upon the piston, cut off at one-fourth the 
stroke, will be 8 1 pounds at the termination of the stroke, 
as shown by the following calculation : 20 pounds added 
to 15 pounds, the pressure of the atmosphere, equal 35 
pounds. This divided by four gives the quotient 81 
pounds. Thus, 8f pounds is the pressure at the termina- 
tion of the stroke, or 6i pounds below atmospheric pressure. 

The tables on pages 49 and 50 show the average press- 
ure of steam upon the piston when cut off at any portion 
of the stroke, beginning at 25 pounds and advancing in 5 
pounds up to 135 pounds per square inch, thereby enabling 
the engineer to determine, at any given pressure, the amount 
of expansion requisite for the full power to be obtained, and 
the saving thereby to be effected. In all cases the pressure 
of the atmosphere must be added to the pressure of the 
steam above' atmosphere, when reference is made to the 
table for the average throughout the stroke. 

Example. — 45 pounds of steam above atmosphere upon 
piston of a high-pressure engine, cut off at one-fourth of 
the length of the stroke. The average pressure through- 
out will be, allowing one pound for friction and back press- 
ure to force out the steam in the cylinder, 191 pounds. 
Thus: 45 pounds of steam cutoff at one-fourth the stroke, 
with 15 pounds added, make 60 pounds. Look for 60 on 
the top line of the table and J on the side. Trace that i 
to the figures under 60, and the average will be found to 
be 351 pounds. Take 16 pounds from 35 1 pounds for 
atmospheric pressure and friction, and there remain 19 i 
pounds, the available average pressure on the piston. 

Example. — 30 pounds cut off at one-third. Add 15 = 45. 
The average in the table will be 311 ; deduct 16 pounds, 
and there remain 15i pounds, the available average press- 
ure upon the piston. 



48 



HAND-BOOK 01^ LAND AND MARINE ENGINES. 



Another Example. — 15 pounds cut off at half-stroke. 
Add 15 = 30. The average in the table will be 25 J. 
Deduct 16 pounds, and 9i pounds remain, the available 
pressure. 

In these examples the steam in the cylinder has ex- 
panded to atmospheric pressure. 

In proportion to the pressure of the steam, the cut-off 
will have to be varied, if the steam is to be expanded to 
its full limit in the cylinder of a non-condensing engine ; 
that is, down to 15 pounds, or equal to the pressure of the 
atmosphere. 

Rule fop ascertaining the Amount of Benefit to be 
depived fpom wopking Steam expansively. — Divide the 
length of the stroke by the length of space into which 
steam is admitted ; find in the annexed table the hyper- 
bolic logarithm nearest to that of the quotient, to which 
add one. The sum is the ratio of gain. 

TABLE 

OF HYPERBOLIC LOGARITHMS TO BE USED IN CONNECTION WITH 
THE ABOVE RULE. 



No. 


Logarithm. 

.22314 


No. 


Logarithm. 

1.60943 


No. 


Logarithm. 

2.19722 


1.25 


5. 


9. 


1.5 


.40546 


5.25 


1.65822 


9.5 


2.25129 


1.75 


.55961 


d.d 


1.70474 


10. 


2.30258 


2. 


.69314 


5.75 


1.74919 


11. 


2.39789 


2.25 


.81093 


6. 


1.79175 


12. 


2.48490 


2.5 


.91629 


6.25 


1.83258 


13. 


2.56494 


2.75 


1.01160 


6,5 


1.87180 


14. 


2.63905 


8. 


1.09861 


6.75 


1.90954 


15. 


2.70805 


3.25 


1.17865 


7. 


1.94591 


16. 


2.77258 


3.5 


1.25276 


7.25 


i.98iao 


17. 


2.83321 


3.75 


1.32175 


7.5 


2.01490 


18. 


2.89037 


4. 


1.38629 


7.75 


2.04769 


19. 


2.94443 


4.25 


1.44691 


8. 


2.07944 


20. 


2.99573 


4.5 


1.50507 


8.5 


2.14006 


21. 


S.04452 


4.75 


1.55814 






22. 


3.09104 



'HAND-BOOK OF LAND AND MARINE ENGINES. 



49 



TABLE 

SHOWING THE AVERAGE PRESSURE OF THE STEAM UPON THE 

PISTON THROUGHOUT THE STROKE, WHEN CUT OFF IN THE 

CYLINDER FROM J TO -^^y COMMENCING WITH 25 POUNDS AND 
ADVANCING IN 5 POUNDS UP TO 75 POUNDS PRESSURE. 



Steam cut off 

in thQ 

Cylinder. 






jure Ie 


















Pres 


L Pounds at the Commencement of the Stroke 




25 


30 


35 


40 


45 


50 


55 


60 


65 1 


70 75 




Avera 


ge Pressure in Pounds upon the Piston. 




■K- 


17i 


21 


24} 


28 


31} 


35 


38} 


42 


45} 


49 


52} 


|- 


23J 


281 


32t 


37} 


42 


46| 


51} 


56} 


61 


65} 


70} 


J 


15 


171 


20t 


231 


26| 


291 


32| 


35| 


38f 


41| 


44| 


1 - 


21 


25i 


29^ 


33f 


38 


42} 


46} 


50f 


55 


59} 


63} 


1 


24 


81f 


332 


38} 


43} 


48} 


53 


571 


62} 


67} 


72} 


-^ 


13 


15} 


18} 


20| 


23} 


26 


28} 


31} 


34 


36} 


39 


1 


19 


23 


26| 


30J 


39} 


38} 


42 


46 


491 


53} 


57} 


* 


22} 


26 


3U 


39} 


40| 


45} 


49f 


54} 


581 


63} 


67f 


i 


23f 


29i 


344 


39 


44 


49 


53J 


58} 


63} 


68} 


731 


i 


Hi 


14 


16} 


18} 


20| 


23} 


25} 


271 


30} 


32} 


34f 


i 


24i 


29} 


34} 


39} 


44} 


49: 


54 


59 


64 


69 


731 


1 


10} 


12^ 


14f 


16f 


18| 


24 


23} 


25} 


.274 


29} 


3I2 


f 


16 


19^- 


22} 


25i 


28f 


32 


35} 


38} 


4l^ 


45 


48} 


f 


19| 


23| 


27| 


31} 


35} 


39} 


43 


47} 


51^ 


55} 


59} 


f 


22i 


26f 


31i 


35} 


40 


442 


49} 


53} 


57f 


62} 


664 




23| 


28} 


33} 


381 


42| 


47i- 


52} 


57} 


62 


66f 


71} 


f 


24i 


29* 


34* 


39} 


44} 


49} 


64} 


59} 


631 


69} 


74i 


9} 


111 


13} 


15} 


17} 


19} 


21} 


23 


25 


27 


281 


1 


18} 


22i 


26 


29J 


S3* 


37 


40f 


44} 


48} 


52 


55i 


1 


22i 


27^ 


32 


36f 


41} 


45} 


60j 


55} 


59| 


64} 


681 


1 


24J 


291 


34| 


39^ 


44} 


49} 


54} 


59^ 


64} 


69} 


74i 


J 


8| 


10} 


12^, 


14} 


15f 


171 


19} 


21} 


23 


24f 


26| 


1 


13J 


16} 


19} 


22} 


25 


271 


30} 


38^ 


36 


381 


41t 


1 


20 


24 


28 


32 


36 


40} 


44- 


48:- 


52^ 


56} 


60} 


i 


22 


26i 


30| 


35} 


39.^ 


44 


48} 


52S 


56^ 


61t 


66 


^ 


24: 

24^ 


29 


34 


381 


43| 


48i 


53- 


58:- 


63:- 


68 


72f 


1 


29| 


34| 


39f 


44* 


49i 


54^ 


59-,- 


64^ 


69} 


74} 


r\ 


7i- 


9} 


10| 


12} 


131 


15} 


16i 


18} 


20 


21} 


23 


A 


12.: 


141 


17} 


19} 


22 


24^ 


27 


29} 


31 1 


34} 

431 


361 


A 


15} 


181 


21J 


25 


28 


31} 


34} 


37} 


40J 


47 


A 


18| 


21 f 


25} 


29} 


32| 


36} 


40} 


43f 


47} 


51 


545 


f\ 




24t 


28} 


32} 


36* 


40i 


44i 


48| 


62i 


561 


60f 


t\ 


21 1 


26i- 


30* 


35 


39} 


431 


48 


521 


56| 


61} 
64| 


65} 


A 


23 


'27} 


32} 


36J 


41} 


46 


50f 


55} 


60 


69} 



D 



GO 



HAND-BOOK OF LAND AND MARINE ENGINES. 



TABLE 

SHOWING THE AVERAGE PRESSURE OF STEAM UPON THE PISTON 
THROUGHOUT THE STROKE, WHEN CUT OFF IN THE CYLINDER 
FROM I TO I, COMMENCING WITH 80 POUNDS AND ADVANCING 
IN 5 POUNDS UP TO 130 POUNDS PRESSURE. 



Steam cut off 

in the 

Cylinder. 




Pressure in ] 


Pounds at the Commencement of the Stroke. , 


80 


85 


90 


95 


100 


105 


110 


115 


120 


125 


130 




i 


Iverag 


e Pres 


sure in Pounds upon the Piston. 


J 


56 


59} 


63 


66i 


70 


73 


77} 


80} 


84 


87} 


91 


f 


75 


79} 


84^ 


89 


93| 


98} 


103 


1071 


112} 


117 


121| 


J 


47| 


50J 


551 


56f 


59| 


621 


95^ 


68} 


71} 


74} 


77} 


^ 


67 1 


72 


76} 


80} 


84-1 


89 


73} 


97} 


101* 


1051 


110 


J 


77i 


82 


87 


91| 


96} 


101} 


106 


111 


115J 


1201 


125} 


- 


41| 


441- 


47 


49} 


52} 


54i 


57:- 


60 


62* 


65} 


671 


i 


61i 


65 


69 


721 


76} 


80} 


84:- 


88 


91| 


95| 


99} 


f 


72.} 


77 


81} 


86 


90} 


95} 


99i 


104} 


1081 


113J 


1171 




78i 


83 


88 


92i 


97f 


102f 


107} 


112} 


117} 


122} 


127} 


i 


37i 


39} 


41| 


444 


46} 


48| 


51 : 


53} 


55f 


58 


60| 


J 


78| 


83i 


88f 


93* 


98} 


103} 


108: 


113} 


118} 


123} 


128 


1 


33^ 


35i 


37f 


40 


42 


44 


46; 


48} 


50} 


52} 


54* 


i 


51} 


54} 


571 


61 


64} 


67} 


70i: 


74 


77} 


80} 


83} 


|- 


63i 


67i 


71} 


75} 


79 


83 


87 


91 


94f 


98f 


102} 


1 


7U 


75f 


80 


84} 


89 


93} 


98 


102J 


1061 


111}'115| 




76} 


81 


85f 


90i 


95} 


100} 


105 


1091 


114} 


119}124 


79 


84 


89 


93| 


98| 


103f 


1081 


113J 


1181 


123}, 128} 


30| 


32| 


34* 


36} 


38} 


40} 


42f 


442 


46} 


48 


50 


f 


59i 


63 


66| 


70j 


74} 


78 


81f 


85} 


89 


92f 


96} 


1 


73- 


78 


82} 


87} 


91| 


96} 


101 


105^ 


110} 


1141 


119} 


i 


79| 


84i 


89} 
3lf 


94- 


99 


104 


109 


114 


119 


124 


1281 


1 


28;: 


30- 


33i 


35} 


37} 


39 


40f 


42} 


44} 


46 




442 


474 


55 


57f 


55} 


58:- 

84^ 


61 


63f 


66f 


69} 


72} 


1 


64: 


68:- 


72^ 


76:- 


80} 


88} 


92} 


96} 


100} 


104} 


^ 


70} 


74f 


79r 


ssi 


88 


92} 


97 


101} 


105| 


110} 


114} 


1 


77l 


82i 


87.- 


92: 


97i 


102 


107 


UIJ 


116f 


121} 


126} 



Rule for finding the Mean op Average Pressure in a 
Cylinder. — Divide the length of the stroke, including the 
clearance at one end of the cylinder, by the distance, in- 



HAI^D-BOOK OF LAND AND MARINE ENGINES. 



51 



eluding the clearance at one end, that steam follows the 
piston before being cut off; the quotient will express the 
relative expansion the steam undergoes. Then find in 
the following table, in the expansion column, the number 
corresponding to this, and take the multiplier opposite to 
it, and multiply the full pressure of the steam per square 
inch, as it enters the cylinder, by it. 



TABLE 

OF MULTIPLIERS BY WHICH TO FIND THE MEAN PRESSURE OF 
STEAM AT VARIOUS POINTS OF CUT-OFF. 



Expansion. 


Multiplier. 


Expansion. 


Multiplier. 


Expansion. 


Multiplier. 


1.0 


1.000 


3.4 


.654 


5.8 


.479 


1.1 


.995 


3.5 


.644 


5.9 


.474 


1.2 


.985 


3.6 


.634 


6. 


.470 


1.3 


.971 


3.7 


.624 


6.1 


.466 


1.4 


.955 


3.8 


.615 


6.2 


.462 


1.5 


.937 


3.9 


.605 


6.3 


.458 


1.6 


.919 


4. 


.597 


6.4 


.454 


1.7 


.900 


4.1 


.588 


6.5 


.450 


1.8 


.882 


4.2 


.580 


6.6 


.446 


1.9 


.864 


4.3 


.572 


6.7 


.442 


2. 


.847 


4.4 


.564 


6.8 


.438 


2.1 


.830 


4.5 


.556 


6.9 


.434 


2.2 


.813 


4.6 


.549 


7. 


.430 


2.3 


.797 


4.7 


.542 


7.1 


.427 


2.4 


.781 


4.8 


.535 


7.2 


.423 


2.5 


.766 


4.9 


.528 


7.3 


.420 


2.6 


.752 


5. 


.522 


7.4 


.417 


2.7 


.738 


5.1 


.516 


7.5 


.414 


2.8 


.725 


5.2 


.510 


7.6 


.411 


2.9 


.712 


5.3 


.504 


7.7 


.408 


3. 


.700 


5.4 


.499 


7.8 


.405 


3.1 


.688 


5.5 


.494 


7.9 


.402 


8.2 


.676 


5.6 


.489 


8. 


.399 


3.3 


.665 


5.7 


.484 







52 HAND-BOOK OF LAND AND MARINE ENGINES. 




HAND-BOOK OF LAND AND MARINE ENGINES. 53 




54 HAND-BOOK OF LAND AND MARINE ENGINES. 

HIGH-PRESSURE OR NON-CONDENSING STEAM- 
ENGINES. 

High-ppessupe, op non-condensing engines are those 
engines in which the steam, after its action on the piston, is 
permitted to escape into the atmosphere, and in which, 
therefore, the pressure of the outgoing steam must exceed 
the atmospheric pressure of 15 pounds to the square inch. 

In this class of engines are included all locomotive, 
fire, and nearly all stationary and river-boat engines, 
which, in turn, comprises a great variety of arrangements 
and designs known as vertical, beam, inclined, oscillating, 
trunk, horizontal, etc. 

If steam at 30 pounds to the square inch above atmo- 
spheric pressure, that is to say, 30 pounds on the steam- 
gauge, be applied to the piston of a high-pressure engine, 
it will exert a force equal to the pressure in the boiler 
above the atmosphere, providing there be sufficient room 
for the steam, and no obstacle to impede its free flow or 
lessen its pressure between the boiler and the cylinder; 
the other side of the piston being open to the atmosphere, 
and the steam having to overcome the atmospheric press- 
ure in its escape from the cylinder, 15 pounds from the 
total pressure of 45 pounds will be lost. 

Advantages of the High-pressupe Engine. — The prin- 
cipal advantages of the high-pressure engine are, its light- 
ness, moderate first cost, economy of space, and the 
facilities it affords for an increase of pressure and speed, 
should it become necessary ; hence, the high-pressure 
engine being lighter, more simple, compact, and less ex- 
pensive in construction, and also less complicated, requir- 
ing less skill to manage and less cost to repair, is more 
desirable for stationary, land, and river-boat purposes than 
the low-pressure engine. 



HAND-BOOK OF LAND AND MARINE ENGINES. 55 

The high-pressure engine is also desirable in marine 
steamers on account of economy of room, weight, etc., 
though objectionable in consequence of its greater con- 
sumption of fuel. The causes which occasion this extra 
consumption of fuel are, first, the steam lost in over- 
coming the pressure of the atmosphere ; second, the loss 
of heat by radiation in consequence of high pressures and 
high temperatures; third, the loss occasioned by the 
escape of heat through the chimney. 

In the high-pressure engine, pressure and speed can be 
increased to any limit within the bounds of safety. Not so, 
however, in the case of the low-pressure, as, with extremely 
high pressures and correspondingly high temperatures, it 
would be impossible to condense the steam, and the result 
would be a loss of power, occasioned by back pressure 
resulting from an imperfect vacuum. 

For all steam-engines with cylinders less than 24 inches 
in diameter, the simple high-pressure or non-condensing 
engine is the most convenient and ecqnomical. 

POWER OF THE STEAM-ENGINE. 

The power which a steam-engine can furnish is generally 
expressed in " horse-power." It will, therefore, be of inter- 
est to engineers, and of special value to many, to have 
briefly stated what is meant by a " horse-power," and how 
it has happened that the power of a steam-engine is thus 
expressed in reference to that of horses. 

Prior to the introduction of the steam-engine, horses 
were very generally used to furnish power to perform 
various kinds of work, and especially the work of pump- 
ing water out of mines, raising coal, etc. For such pur- 
poses, several horses working together were required. Thus, 
to work the pumps of a certain mine, five, six, seven, or 



56 HAND-BOOK OP LAND AND MARINE ENGINES. 

even twenty-five horses were found necessary. When it 
was proposed to substitute the new power of steam, the 
proposal naturally took the form of furnishing a steam- 
engine capable of doing the work of the number of horses 
used at the same time. Hence, naturally followed the 
usage of stating the number of horses which a particular 
engine was equal to, that is, its " horse-power." 

But as the two powers were only alike in their equal 
capacity to do the same w^ork, it became necessary to refer 
in both powers to some work of a similar character which 
could be made the basis of comparison. Of this character 
was the work of raising a weight perpendicularly. 

A certain number of horses could raise a certain weight, 
as of coal out of a mine, at a certain speed ; a steam- 
engine, of certain dimensions and supply of steam, could 
raise the same weight at the same speed. Thus, the weight 
raised at a known speed could be made the common meas- 
ure of the two powers. To use this common measure it 
was necessary to know what was the power of one horse in 
raising a weight at a known speed. 

By observation and experiment it was ascertained that, 
referring to the average of horses, the most advantageous 
speed for work was at the rate of two-and-a-half miles per 
hour — that, at that rate, he could work eight hours per day, 
raising perpendicularly from 100 to 150 pounds. The 
higher of these weights was taken by Watt, that is, 150 
pounds at 2 J miles per hour. But this fact can be express- 
ed in another form : 2i miles per hour is 220 feet per minute 
^ 2K X 5280 ^ 220). So, the power of a horse was taken at 
150 pounds, raised perpendicularly, at the rate of 220 feet 
per minute. This also can be expressed in another form : 
The same power which will raise 150 pounds 220 feet high 
each minute, will raise 



HAND-BOOK OF LAND AND MARINE ENGINES. 57 

300 pounds 110 feet high each minute. 
3,000 " 11 " " 
33,000 " 1 foot " 

For in each case the total work done is the same, viz., 
same number of pounds raised one foot in one minute. 

If it is clearly perceived that 33,000 pounds, raised at 
the rate of one foot high in a minute, is the equivalent 
of 150 pounds at the rate of 220 feet per minute (or 2J 
miles per hour), it will be fully understood how it is that 
33,000 pounds, raised at the rate of one foot per minute, 
expresses the power of one horse, and has been taken as 
the standard measure of power. 

It has thus happened that the mode of designating the 
power of a steam-engine has been by " horse-power," and 
that one horse-power, expressed in pounds raised, is a 
power that raises 33,000 pounds one foot each minute. 
This unit of power is now universally received. Having 
a horse- power expressed in pounds raised, it was easy to 
state the power of a steam-engine in horse-power, which 
was done in the following manner : 

The force with which steam acts is usually expressed 
in its pressure in pounds on each square inch. The piston 
of a high-pressure steam-engine is under the action of the 
pressure, of steam from the boiler, on one side of the piston, 
and of the back action of the pressure due to the discharg- 
ing steam, on the other side. The difference between the 
two pressures is the effective pressure on the piston ; and 
the power developed by the motion of the piston, under 
this pressure, will be according to the number of square 
inches acted on and the speed per minute with which the 
piston is assumed to move. 

Thus, let the number of square inches in the surface of the 
piston of a steam-engine be 100, and the effective pressure on 
each square inch be 33 pounds, and the movement of the 



5S HAND-BOOK OF LAND AND MARINE ENGINES. 

piston be at the rate of 200 feet per minute, then the total 
eifective pressure on the piston will be 100 X 33 = 3300 
pounds, and the movement being 200 feet per minute, the 
piston will move with a power equal to raising 660,000 
pounds one foot high each minute, (as 3300 X 200 = 660,- 
000,) and as each 33,000 pounds raised one foot high is 
one-horse power, and ^^^ is 20, then the power of this en- 
gine is 20-horse power. If this power is used to do work, 
a part of it will be expended in overcoming the friction 
of the parts of the engine and of the machinery through 
which the power Is transmitted to perform the work. The 
calculation made refers to the total power developed by 
the movement of the piston under the pressure of steam. 

The number of feet moved by the piston each minute is 
known from the length of stroke of piston in feet, and 
number of revolutions of engine per minute, there being 
two strokes of the piston for each revolution of the engine. 
When these three facts are known, the power of an engine 
can be readily and accurately ascertained ; and it is evident 
that, without the knowledge of each of the facts, viz., 
square inches of piston, effective pressure on each square 
inch, and movement of piston per minute, the power can- 
not be known. 

But circumstances, especially those existing when the 
condensing-engine was introduced by Watt, led to assump- 
tions as to pressure per square inch and speed of piston 
which, though true at the time, have long since ceased to 
be true, and consequently the rules based on such assump- 
tions are entirely inapplicable, and when used must of 
necessity give false statements. 

With regard to how much is understood by a horse- 
power, there is in this country no question at all. Horses 
vary in their ability to endure protracted labor, and our 
standard may be more or less than the average of horses 



HAND-BOOK OF LAND AND MARINE ENGINES. 



59 



are able to do ; but that is of little importance. So long as 
the number of horse-power of an engine conveys a definite 
knowledge of its power, it is of little consequence what 
relation it sustains to the action of any particular class of 
animals. 



FOREIGN TERMS AND UNITS FOR HORSE-POWER. 


Countries. 


Terms. 


E|ig. translation. 


Units. 


English equivalent. 


English. 
French. 
German. 
Swedish. 
Russian. 


Horse-power. 
Force de cheval. 
Pferde-krafte. 
Hast-kraft. 
Syl-lochad. 


Horse-power 

Force-horse. 

Horse-force. 

Horse-force. 

Force-horse. 


550 foot-pounds. 
75 kilogr. metres. 
513 Fuss-funde. 
600Skalpund-fot. 
550 Fyt-funt. 


550 foot-pounds. 
542.47 foot-pounds. 
582.25 foot-pounds. 
542.06 foot-pounds. 
550 foot-pounds. 



The French apply the term force de cheval to a power 
capable of raising 4*5000 kilogrammes 1 metre high in 1 
minute, which is equal to a force capable of raising 32,549 
pounds 1 foot high in a minute, which is about ^^^ less than 
our unit of measure. 



Horse-power. 


Force de cheval. 


Horse-power. 


Force dQ cheval. 


10 


10.14 


60 


60.83 


15 


15.20 


65 


65.89 


V 20 


20.28 


70 


70.97 


25 


25.34 


75 


76.03 


30 


80.41 


80 


81.11 


35 


85.48 


85 


86.17 


40 


40.55 


90 


91.25 


45 


45.62 


95 


96.31 


50 


50.69 


100 


101.8856 


55 


55.75 







In this country, and also in England, it has been usual 
to assign a certain horse-power for a high-pressure engine 
of certain dimensions ; thus, an engine having a cylinder 
10 inches in diameter and 24 inches stroke of piston 



60 HAND-BOOK OF LAND AND MARINE ENGINES. 

would be called a 25-horse-power engine, and so on with 
high-pressure engines of all dimensions. But it is utterly 
impossible to say what horse-power an engine of the above 
dimensions would be, unless we knew the effective pressure 
to be exerted against the piston, and also the speed at 
which the piston is intended to move. 

There are several kinds of horse-power referred to in 
connection with the steam-engine, — the " nominal," " indi- 
cated," " actual or net," " dynamometrical," and " com- 
mercial." 

The nominal horse-power is admitted to be a force 
capable of raising a weight of 33,000 pounds one foot 
high in one minute, or 150 pounds 220 feet high in the 
same length of time. The term '* nGminal horse-power/' as 
before stated, originated at the time of the discovery of 
the steam-engine, from the necessity which then arose for 
comparing its powers with those of the prevailing motor. 
The nominal horse-power was based on the general princi- 
ple of the age, which dealt with low pressures and slow 
piston speeds. These quantities have of late years been 
greatly increased, and the old formula, in consequence, has 
become of less importance as a true expression of relative 
capacity. Hence, the term nominal horse-power is in reality 
of itself nominal, as Watt, in order to have his engines 
give satisfaction, added some twenty-five per cent, to the 
real work of the best horses in Cornwall, 

But the term nominal horse-power implies the ability to 
do so much work in a certain period of time ; and, in 
order to have a proper idea of it, a unit of measure is also 
employed. This unit is called a horse-power, and, as 
before stated, is equal to 33,000 pounds raised through a 
space of one foot in one minute : it is the execution of 
33,000 foot-pounds of work in one minute. 

Work is performed when a pressure is exerted upon a 



HAND-BOOK OF LAND AND MARINE ENGINES. 61 

body, and the body is thereby moved through space. The 
unit of pressure is one pound, the unit of space one foot, 
and work is measured by a "foot-pound" as a unit. 
Thus, if a pressure of so many pounds be exerted through 
a space of so many feet, the number of pounds is multi- 
plied into the number of feet, and the product is the 
number of foot-pounds of work ; hence, if the stroke of a 
steam-engine be seven feet, and the pressure on each square 
inch of the piston be 22 pounds, the work done at each 
single stroke, for each square inch of the piston, will be 7 
multiplied by 22, equal to 154 foot-pounds. 

Indicated Horse-power.— The indicated horse-power is 
obtained by multiplying together the mean effective press- 
ure nn the cylinder in pounds per square inch, the area 
of the piston in square inches, and the speed of the piston 
in feet per minute, and dividing the product by 33,000 ; 
and as the effective pressure on the piston is measured by 
an instrument called the indicator, the power calculated 
therefrom is called the indicated horse-power. 

Actual or Net Horse-power. — The actual or net horse- 
power expresses the total available power of an engine ; 
hence it equals the indicated horse-power less an amount 
expended in overcoming the friction. The latter has two 
components, viz., the power required to run the engine, de- 
tached from its load', at the normal speed, and that re- 
quired when it is connected with its load. For instance, 
if an engine is desired to drive 10 machines, each requir- 
ing 10-horse power, it should be of sufficient size to furnish 
100 net horse-power ; but to produce this would require 
about 115 or/ 20 indicated horse-power. The net horse- 
power of an engine may be determined by subtracting 
from the indicated horse-power the power required to over- 
come the friction of the engine when in the regular per- 
formance of its duty. 
G 



62 HAND-BOOK OF LAND AND MARINE ENGINES. 

Dynamometpical Horse-powep. — The dynamometrical 

horse-power is the net power of the engine after allowing 
for friction, etc., and this alone is the power with which 
users of steam-engines are concerned. Though not equal 
in point of accuracy to the indicator, the dynamometer 
gives the actual power of small engines near enough for 
all practical purposes ; but it cannot be conveniently ap- 
plied to large engines. 

Commercial Horse-powep. — The term commercial 
horse-power is not generally used, and, when used, has no 
definite meaning, as there is no recognized standard in use 
among engineers and manufacturers by which to buy and 
sell engines. Though the question has often been discussed, 
and its importance generally recognized, it has never been 
universally adopted, consequently, the nominal horse- 
power of a steam-engine means anything that the manu- 
facturer feels disposed to call it. It seems very strange 
that this should be so, as every civilized country has its 
standard of weights and measures, with strict laws com- 
pelling the observance of these standards in the various 
operations of trade. The public, also, are keenly alive to 
the importance of these regulations, and no purchaser is 
so unmindful of his own interests as not to insist on ob- 
taining the full weight of most articles for which he pays ; 
but steam-engines are almost universally bought and sold 
by a system of guess-work which would not for a mo- 
ment be tolerated, were it attempted to be practised in 
any other branch of trade. There is great need of some 
recognized standard that would designate the number of 
square inches in the cylinder, travel of piston in feet per 
minute, and average steam pressure through the length of 
stroke, that should constitute the commercial horse-power 
of engines, say, for instance, 4 square inches in the 
cylinder, a piston speed of 240 feet per minute, and an 



1 



HAND-BOOK OF LAND AND MARINE ENGINES. 63 

average pressure of 40 pounds per square inch; such 
proportions would be capable of developing a horse-power 
in most ordinary high-pressure engines, without the neces- 
sity of excessive speed or undue straining. 

Small engines are generally more economical than large 
ones, where the steam pressures, points of cat-off, and 
power developed are the same ; for, although the smaller 
engine, at the same speed, would be less economical at 
the higher speed necessary to produce the same power, 
the gain due to high speed overbalances the loss due 
to the smaller size of cylinder. 

Engines too large for the work to be done are less eco- 
nomical than if proportionate to the power required ; for 
instance, an engine of 40-horse power doing the work of 
20-horse power, and running at a high speed, the steam 
would necessarily have to be throttled down by the gov- 
ernor from, say, 60 or 70 pounds boiler pressure to 25 or 
30 pounds on the piston, which would be a loss of nearly 
I in fuel, as the loss by atmospheric pressure in non-con- 
densing engines is equally as much for 25 pounds as for 
100 pounds pressure. 

The steam necessary to drive a 40-horse power high- 
pressure engine with 7io load, would give more than 10- 
horse power in a small engine. The cylinder of any 
engine should be of sufficient size to give the full power 
required, leaving a reasonable margin for variation in 
pressure, and for recuperative power under sudden in- 
crease of load, and no larger. Large engines doing the 
work easily, and at a low pressure, are economical only 
when the speed is reduced in proportion to the work to be 
done. 

There are three conditions which influence the economy 
of non-condensing steam-engines : steam pressure, expan- 
sion, and speed of piston ; for it will be found, on selecting 



64 HAND-BOOK OF LAND AND MARINE ENGINES. 

any particular horse-poweVy that the highest steam press- 
ures and revolutions and shortest points of cut-off are 
those which show the greatest economy of steam. When 
these three conditions are all favorable at the same time, 
the maximum economy is obtained ; but when one or more 
only is favorable, the results are so modified as often to 
appear contradictory. 

Effective Pressure against the Piston. — The character 
of the connections between the boiler and cylinder, their 
length, degree of protection, number of bends, shape of 
valves, etc., must all be considered in forming an estimate 
of the initial steam pressure in the cylinder; while the 
effective pressure will depend upon the point at which the 
steam is cut ofi*, and the freedom with which it exhausts ; 
as it has been fully demonstrated by experience that the 
efiective pressure against the piston in the cylinder of 
steam-engines, more particularly slide-valve engines, 
rarely, if ever, exceeds t of the boiler pressure, as the 
free flow of the steam from the boiler to the cylinder is 
obstructed by the action of the governor and affected by 
the character of the connection, as before stated, so that 
in calculating the horse-power of steam-engines, not more 
than t of the boiler pressure should be taken as the 
effective pressure in the cylinder. 

When comparing the relative merits of different en- 
gines, it is of more importance to steam users to look 
at the actual power an engine is capable of exerting, 
rather than at the stated nominal horse-power or size of 
cylinder ; as it is no uncommon thing with two engines of 
the same diameter of cylinder and the same general pro- 
portions, that one may be capable of developing much 
more power than the other, even with a less consumption 
of coal per actual horse-power. 

The nominal horse-power of a high-pressure engine, 
though never very definitely defined, should obviously 



HAND-BOOK OF LAND AND MARINE ENGINES. 65 

hold the same relation to the actual power as that which 
obtains in the case of condensing engines, so that an en- 
gine of a given nominal power may be capable of perform- 
ing the same work, whether high pressure or condensing. 
But whether it does or not, the standard of a horse-power 
serves as a standard of comparison, and its utility as a 
unit of reference is not impaired, whether it represents the 
actual power of one horse or three, so long as the standard 
is universal. The following rule will be found very con- 
venient for those who may have occasion to estimate the 
horse-power of high-pressure or non-condensing steam- 
engines, as it is practical and correct. 

Rule fop finding the Hopse-power of Steam-engines. 
— Multiply the area of the piston by the average steam 
pressure per square inch ; multiply this product by the 
travel of piston in feet per minute ; divide this product 
by 33,000, and the quotient will be the horse-power. 

EXAMPLE I. 
Diameter of cylinder iu inches 10 

10 

Square of diameter of cylinder 100 

Multiplied by the decimal .7854 

Area of piston 78.54 inches. 

Boiler pressure, 60 pounds ; cut-off, i stroke, ] 
Average pressure in cylinder, 50 pounds;* V 45 lbs. 

5 off for loss by condensation, etc., J 

39270 
31416 

3534.30 
Travel of piston in feet per minute f 250 

Divide by 33,000)883575.00 

26. horse-pow. 

* See Tables of Average Pressures, pages 49, 60. 

t To find the Travel of Piston in Feet per Minute. — Multiply the distance travelled 
for one stroke in inches by the whole number of strokes in inches, and divide 
by 12. ^ 

6* E 



66 HAND-BOOK OF LAND AND MARINE ENGINES. 

EXAMPLE II. 

Diameter of cylinder in inches 10 

10 

Square of diameter of cylinder 100 

Multiplied by .7854 

Area of piston 78.54 inches. 

Boiler pressure, 80 pounds ; cut-off, I stroke, ] 
Average pressure in cylinder, 47| pounds ; > 42.75 lbs. 

5 off for loss by condensation, etc., J 

39270 
54978 
15708 
31416 

3357.5850 
Travel of piston in feet per minute, 300 

Divided by 33,000)1007275.5000 

30.* horse-power. 

EXAMPLE III. 

Diameter of cylinder in inches 20 

20 

Square of diameter of cylinder 400 

Multiplied by .7854 

Area of piston 314.1600 

Boiler pressure, 60 pounds ; cut-off, | stroke, ) 
Average pressure in cylinder, 57 pounds ; V 52 lbs. 

5 off for loss by condensation, etc., J 

6283200 
15708000 

16336.3200 
Travel of piston in feet per minute, 300 

Divided by 33,000)4900896.0000 

148.* horse-power. 
* In these examples, the fractional parts of a horse-power have been 
intentionally left out. 



HAITD-BOOK OF LAND AND MARINE ENGINES. 67 

EXAMPLE IV. 

Diameter of cylinder in inches 20 

20 

Square of diameter of cylinder 400 

Multiplied by 7854 

Area of piston 314.1600 inches. 

Boiler pressure, 85 pounds ; cut-off, i stroke, | 
Average pressure in cylinder, 50 pounds; > 45 lbs. 

o off for loss by condensation, etc., J 

15708000 
12566400 

14137.2000 
Travel of piston in feet per minute 350 

7068600000 
424116000 

Divided by 33,000)4948020.0000 

149. horse-power. 

It will be seen from the foregoing examples, that any 
increase of pressure and piston speed makes a very notice- 
able difference in the power of the engine ; but this aug- 
mentation of power is not obtained without an increased 
quantity of steam in proportion to the increased pressure 
and speed, except where the steam is expanded to its 
lowest available limits. 

A high-pressure engine, for instance, working with 40 
pounds steam above the atmospheric pressure upon the 
piston, cut off at one-third, and expanding the remainder 
of the stroke, the piston travelling 220 feet per minute, 
would only exert the power for which it was nominally 
calculated, independent of friction ; but take the same en- 
gine, and increase the speed from 220 to 440 feet per 
minute, — which is quite practicable, — the power of that 
engine would then be doubled, less the extra friction ; but 
double the quantity of steam would have been used. 



68 



HAND-BOOK OF LAND AND MARINE ENGINES. 



Suppose steam at 80 pounds pressure was introduced to 
the same cylinder, cut off at one-third and worked expan- 
sively, as in the first case, the power given out by the 80 
pounds pressure would be less in proportion than that at 
40 pounds, as the exhaust would be thrown away at about 
five times the pressure that it was at 40 pounds, and a 
portion of the useful effect of the steam would be lost, in 
consequence of its not being expanded to its full limit, the 
lost portion escaping into the atmosphere and exerting a 
corresponding back pressure on the piston. 

The following method will be found very convenient, as 
it somewhat abbreviates the rule used in the foregoing ex- 
amples for calculating the horse-power of a steam-engine. 

TABLE OF FACTOES. 



Diameter of 




Diameter of 




Cylinder in 


Factor. 


Cylinder in 


Factor. 


Inches. 




Inches. 




8 


.152 


26 


1.608 


10 


.238 


30 


2.142 


12 


.342 


36 


3.084 


14 


.466 


40 


3.808 


16 


.609 


45 


4.82 


18 


.771 


48 


5.483 


20 


.952 


50 


5.95 


22 


1.151 


56 


7.463 


24 


1.37 


60 

1 


8.'568 



Rule. — Multiply the factor of the given diameter of 
cylinder by the speed of piston in feet per minute (using 
all below hundreds as decimals) ; multiply the product by 
the average pressure in pounds per square inch. This last 
product will be the horse-power of the engine. 



HAND-BOOK OF LAND AND MAEINE ENGINES. 69 

EXAMPLE. 

Diameter of cylinder, 12 inches, .342 

2.40 



Travel of piston per minute, 240 feet, 13680 

684 

Average pressure, 42 pounds, .82080 

42 

164160 
328320 



34.47360 horse-power. 

Bourne's Rule for ascertaining the nominal horse-power 
of a high-pressure steam-engine working about four times 
the usual speed. 

Multiply the square of the diameter of the cylinder by 
the pressure on the piston per square inch less a pound 
and a half, and by the cube root of the stroke in feet, and 
divide the product by 235. The quotient is the power of 
the high-speed engine in nominal horse-power. 

EXAMPLE. 
Diameter of cylinder, 20 

20 

400 sq. of diameter. 
Pressure per sq. in. 80 lbs., less 1^^ lbs., 78 J 
Stroke 36 inches = 3 feet, 31400 

1.4422496 
Divisor, 235)45286.6374400(192.7 n. h. p. 

Colbupn's Rule is to multiply the area of the piston, the 
pressure of steam per square inch, the number of revolu- 
tions per minute, and the length of stroke together ; divide 
the product by 33,000, and take /^ of the quotient. But 
Colburn's rule is not correct, as only one-half the piston 
speed is employed to get the power of the engine. In fact, 
neither Colburn's nor Bowen's rules are correct. 



70 HAND-BOOK OF LAND AND MARINE ENGINES. 

WASTE IN THE STEAM-ENGINE. 

A pound of good coal, it is universally admitted, will 
liberate, during complete combustion, over 14,500 units of 
heat, each unit being equivalent to 772 foot-pounds. The 
mechanical equivalent of the heat developed by the com- 
bustion of a pound of coal is, therefore, say 14,500 X 772 
= 11,000,000 foot-pounds. A horse-power is always as- 
sumed to be equal to 33,000 foot-pounds per minute, or 
1,980,000 foot-pounds per hour. 

So, the combustion of each pound of coal per hour lib- 
erates heat enough to develop 11,000,000 -r- 1,980,000 = 
say 5-horse power ; and in a perfect steam-engine the con- 
sumption of coal would be about at the rate of one-fifth of 
a pound per hour for each horse-power developed. 

The greatest economy yet obtained in the best high- 
pressure engines may be taken at from 3 to 4 pounds of 
coal per indicated horse-power per hour ; but for ordinary 
high-pressure engines in this country and in England a 
consumption of from 7 to 9 pounds is quite common. In 
good modern high-pressure steam-engines the useful effect 
obtained from the work stored up in the fuel may be thus 
calculated : 

Lost through bad firing and incomplete combustion 10 per cent. 
Carried off by draft through chimney 30 " " 

Carried away in the exhaust steam 50 " " 

Utilized in motive power (indicated) 10 " " 

100 

The minor causes of loss in the steam-engine are 

radiation of heat from the boiler, steam-pipes, and cylinder, 
leakage and condensation ; but the great loss arises from 
the escape of the steam into the atmosphere with only a 
small portion of its heat utilized ; this of itself leads to a 
loss of from 40 to 60 per cent. ; a further loss of useful 



I 



HAND-BOOK OF LAXD ANp MAEINE EKGINES. 



71 



X 



o 
o 

(0 



o 

X 
3Q 



c 

30 

m 

O 

C 
H 



z 
o 




72 HAND-BOOK OF LANP AND MARINE ENGINES. 

effect in the steam-engine ensues from a portion of the 
motive power actually developed being absorbed by fric- 
tion, the useful power of the engine being frequently 
reduced by this cause by from 10 to 15 per cent. 

The use of good material, good workmanship, thorough 
lubrication and cleanliness, it is true, go far to lessen the 
friction and increase the efficiency of steam-engines; so 
also the use of high-pressure steam, high rates of expan- 
sion, efficient feed-water heaters, non-conductors and steam- 
packing, is conducive to economy ; but what is needed to 
render the steam-engine what it should be, is complete 
combustion of the fuel in the furnace, the transfer of all 
the heat generated to the water in the boiler, the passage 
of the steam through the engine without the loss of heat, 
except such as is converted into motive power, the trans- 
mission of the remaining heat in the exhaust steam to the 
feed water, and the absence of friction in its working 
parts. 

In consequence of the enormous waste incurred in the 
use of the steam-engine, numerous attempts have been 
made to supersede steam as a prime mover, but as yet 
without success, as there are certain, difficulties connected 
with the employment of all other agents which have as 
yet proved insurmountable. In short, there is not at 
present on the horizon the faintest dawn of the appearance 
of any mode of generating force calculated to compete 
with, much less to supersede, the steam-engine. 

Electro-magnetism, from which, at one time, so much 
was expected, is now thoroughly understood to be a far 
more costly mode of obtaining power than the combus- 
tion of coal. Heat, electricity, magnetism, chemical 
affinity, force, are all equivalent to each other, according 
to ratios which are fixed and unalterable. The atomic 
weight of carbon is 6 ; that of zinc, 32. One pound of carbon 



HAND-BOOK OF LAl^D AND MARINE ENGINES. 73 

will develop more heat, and consequently more force, than 
6 pounds of zinc ; whilst, weight for weight, the cost of the 
former to the latter is as 1 to 50. 

The discovery of a new motor, even if such a thing 
should happen, would take a quarter of a century to 
replace the present arrangements ; and even then it would 
be the duty of the engineer and the inventor to strive to 
improve the modes of employing the agent we now pos- 
sess, and to inquire in w^hich direction further progress in 
its economical application would lead. 

That great improvements can and will be made in the 
economical working of the steam-engine, none can doubt, 
who have compared its theoretical capabilities with its 
present performances. 

DESIGN OF STEAM-ENGINES. 

The most valuable features of a steam-engine are 
strength, durability, simplicity, and economy ; therefore, in 
designing an engine, symmetry should be observed, in 
order that all the working parts may be accessible with- 
out any disarrangement of details ; lightness should also 
be adhered to as far as compatible with strength. 

The economical working of a steam-engine depends 
upon many things, — proportions of design, good work- 
manship, care in using the materials employed in its con- 
struction, and a skilful adjustment of the different parts ; 
as the resistance of every machine is increased or dimin- 
ished according to the harmony of proportions existing 
between its different principal parts. 

The wear of the shaft, the burden on the beam, the 
wear and tear of the cylinders and packing-rings, the 
weight borne by the guides in sustaining or directing the 
cross-head, should all be duly considered by the designing 
engineer. 
7 



74 HAND-BOOK OF LAND AND MARINE ENGINES. 

Steam-engines embrace a great variety of designs, viz., 
the vertical, inclined, inverted, beam, horizontal, side-lever, 
oscillating, trunk, steeple, etc. Those most generally used 
for stationary engines are the horizontal, vertical, and 
beam ; but there is no other form which stands the tests 
and meets the public wants as does the horizontal ; as an 
evidence of which, wherever steam-engines of great power 
are required, the horizontal style of engine is better liked 
than any other type. 

THE BED-PLATE. 

The bed, or bed-plate, should be cast in one piece when- 
ever the circumstance of design, construction, etc., will per- 
mit. The metal should be so distributed as to give it the 
necessary resisting strength without excessive weight, as it 
is not always the heaviest bed-plates that possess the 
greatest rigidity. 

CYLINDERS. 

The cylinder being one of the most important and ex- 
pensive parts of the steam-engine, in order to render it 
durable and reliable, it should be mathematically correct 
as to its inside diameter from end to end ; though, un- 
fortunately, this is not always the case. But there are 
several reasons which may be assigned as the cause of 
irregularities in the bore of steam cylinders, — the machine 
with which it is bored, the kind of tool used, speed of 
cutter, want of uniformity in the casting, etc. 

Experience has shown it to be advisable, when circum- 
stances will permit, to bore cylinders upright, taking out 
a heavy cut at first, and then bringing the interior of the 
cylinder, by successive cuts, to within ^^^ ^^ ^^ '^^^^ ^^ ^^^ 
required size ; the remaining portion should then be re- 



HAND-BOOK OF LAND AND MARINE ENGINES. 



75 



moved by a cutter which would be neither round nor 
diamond pointed, but a kind of combination of the two. 

It is not at all desirable that a cylinder when bored 
should present a dead smooth surface, as such surfaces in 
steam cylinders do not wear so well at the outset as those 
slightly ridged. This may be accounted for by the extent 
of surface to be worn down to a steam-tight bearing. 

Cylinders should never be removed from the bed-plate 
for the purpose of reboring, unless it be found impractica- 
ble to perform that operation while in its original position ; 
as, if the cylinder be out of line and the crank-pin be in 
line, the cylinder can be rebored in line with the crank- 
pin ; or if, as is often the case, the crank-pin be out of line 
with the cylinder, the pin can be removed and the hole in 
the crank rebored in accurate line with the cylinder. Of 
course, in such cases, it becomes necessary to have a new 
crank-pin. 

The thickness of steam cylinders cannot be deduced 
from any fixed rule which would be practical in all cases. 
For instance, a cylinder 6 inches in diameter should equal 
at least | of an inch in thickness ; whereas one 24 inches 
in diameter would be 1^ inches in thickness : the former 
equals -^q of the diameter, while the latter equals j^q of 
the diameter. 



TABLE 

SHOWING THE PROPER THICKNESS FOR STEAM CYLINDERS OF 
DIFFERENT DIAMETERS. 



Diam. of 
Cylinder. 


Thickness. 


Diam. of 
Cylinder. 


Thickness. 


6 inch. 


1 inch. 


14 inch. 


1 inch. 


8 - 

9 " 

10 *' 

11 ** 




15 '* 

17 ** 

18 »* 

19 ^* 


1?" 

it :: 


12 " 


H " 


21 - 


If " 



76 



HAND-BOOK OF LAND AND MARINE ENGINES. 



The foregoing thicknesses include the proper allowance 
for reboring. But when the speed of the piston is intended 
to exceed 300 feet per minute, y'g of an inch should be 
added per 100 feet to the thickness given. 

The following table, however, is more in accordance 
with modern practice. 



Diam. of 
Cylinder. 


Thickness. 


Diam. of 
Cylinder. 


Thickness. 


6 in. 


.440 


18 in. 


1.070 


8 *' 


.545 


20 ** 


1.176 


10 *' 


.650 


22 ^* 


1.280 


12 '' 


.755 


24 " 


1.385 


14 '' 


.860 


26 *' 


1.490 


16 '* 


.965 


28 " 


1.595 






30 *' 


1.700 



Rule for finding the required Diameter of Cylinder for an 
Engine of any given Horse-power ^ the Travel of Piston and 
available Pressure being decided upon, — Multiply 33,000 by 
the number of horse-power ; multiply the travel of piston 
in feet per minute by the available pressure in the cylin- 
der. Divide the first product by the second ; divide the 
quotient by the decimal "7854. The square root of the 
last quotient will be the required diameter of cylinder. 

PISTONS. 
The piston ranks next in importance to the cylinder, 
as the quantity of fuel consumed, the useful effect of the 
steam, the amount of power developed by the engine, etc., 
depend in a great measure on the character and condition 
of the piston. It is, therefore, not to be wondered at, that 
an immense amount of thought and mechanical skill has 
been devoted to its improvement, and that its condition is 
more frequently a source of loss and anxiety to owners of 
steam-engines, and annoyance to the engineer, than any 
other detail of the steam-engine. 



HAND-BOOK OF LAND AND MARINE ENGINES. 77 

PISTON-RINGS. 

Piston-rings should be of a softer material than that of 
the cylinder, in order to prevent as far as possible the 
wear of the latter instead of the rings, as the expense of 
renewing them is trifling compared with that of reboring 
the cylinder. Cast-iron is very generally used, as it pos- 
sesses very many advantages for this purpose, among which 
are cheapness, durability, uniform expansion, and the ad- 
ditional advantage that it acquires a finer surface and 
generates less friction than any other material that may 
be used; although brass rings faced with Babbit-metal 
are very frequently used for the pistons of locomotives 
and marine engines. 

Piston-rings should be fitted so as to move freely between 
the flange of the piston-head and the follower-plate, in 
order that they may accommodate any inequality that 
may exist in the cylinder ; and as their edges are liable to 
corrode and become leaky, they should be frequently re- 
moved from the cylinder and faced-up in a lathe, and re- 
ground, and fitted to the flange and follower-plate. 

PISTON-SPRINGS. 

There is not, in the whole range of steam engineering, 

it may be safely said, a subject on which the inquiring 
engineer finds such a dearth of information as he does in 
regard to the proper amount of elasticity required for the 
elliptic springs so generally used in adjusting or setting 
out piston-packing. For, while some bear a slight resem- 
blance to, and possess some of the qualities of, an elliptic 
spring, others can be said to be nothing more than un- 
shapely pieces of steel. 

If any engineer wishes to test the elasticity of such 
springs, let him place the extreme points of one on two 



78 HAND-BOOK OF LAND AND MARINE ENGINES. 

parallel pieces of iron, and place weights on it, and observe 
the enormous load it requires to deflect the spring even 3^^' 
of an inch in its centre ; this will enable him to form some 
idea of the amount of friction produced in steam cylinders 
by badly proportioned springs. Such springs, w^hen pressed 
against the packing-rings by means of set-screws, are as 
rigid as jack-screws, or solid blocks of iron, and possess no 
advantages over solid pistons, save that they can be read- 
justed to take up the wear. 

The pistons of large marine engines generally have 
lighter springs than many small engines, and are not 
packed so tight by many degrees pressure, in proportion 
to their areas, as some stationary engines. This may be 
accounted for by the fact, that pistons that would be per- 
fectly steam-tight under a pressure of 25 to 30 pounds to 
the square inch, would be apt to leak excessively under a 
pressure of from 80 to 100 pounds. 

STEAM-PISTONS. 
The chief merits of the steam-piston seem to consist in 
its diminished friction and first cost, as it can be more 
cheaply constructed than spring-pistons, and, after being 
once put in the cylinder, requires no further attention or 
adjustment on the part of the engineer; but it is claimed, 
by its opponents, that it is liable to leak, and wear the cyl- 
inder out of "true,'' in consequence of its being influenced 
by varying steam pressures. Nevertheless, the steam- 
piston, after encountering a good deal of prejudice, like 
many other innovations in steam engineering, is fast estab- 
lishing its merits with engineers and steam users. 

SOLID PISTONS. 
Solid pistons are sometimes used, and, when well de- 
signed and fitted, answer very well, as they have the ad- 



HAND-BOOK OF LAND AND MARINE ENGINES. 79 

vantage of producing no friction ; but they are only prac- 
ticable in cases where the cylinder is of uniform bore all 
through, and the engine is perfectly in line. They have 
the disadvantage of not being adjustable when they become 
worn or leaky ; although there is one solid piston, " Bucks 
Patent," that can be adjusted to the cylinder more accu- 
rately than any spring-piston. 

The pistons of steam-hammeps are generally made 
solid, and are kept steam-tight by turning grooves around 
the head, into which narrow steel or wrought-iron rings are 
sprung, which adjust themselves to the form of the cyl- 
inder, it being the only kind of piston-head capable of 
resisting the immense jar to which the mass is subjected. 
The pistons of small steam-engines are frequently made in 
the same way, as they are found to be very cheap and 
convenient. 

TABLE 

OF PISTON SPEEDS FOR ALL CLASSES OF ENGINES — STATIONARY, 
LOCOMOTIVE, AND MARINE. 

Small Stationary Engines, 200 to 250 feet per minute. 

Average 225 " 

Large Stationary Engines, 275 to 350 " 

Average about 312 " 

Corliss Engines, 400 to 500 " 

Average 450 " 

Locomotives and Allen Engines, 600 to 800 " 

Average 700 " 

Engines of River Steamers, 400 to 500 " 

Average 450 " 

Engines of Ocean Steamers, 400 to 600 " 

Average 500 " 



80 



HAND-BOOK OF LAND AND MARINE ENGINES. 



PISTON, CONNECTING-ROD, AND CRANK CONNECTION. 




The annexed cut shows the position of the piston in the 
cylinder when the crank is at half stroke. It will be ob- 
served that the piston is ahead of its proper position 
throughout the forward stroke, and that it must of neces- 
sity lag behind its position on the return-stroke, and that 
the points of full power are not on exactly the opposite 
sides of the diameter of the circle described by the crank, 
and that a straight line passing through the centre of the 
crank-shaft cannot intersect both points. These irregu- 
larities, which are due to the influence of the crank and 
connecting-rod, entirely disappear at the end of each 
stroke. 

The crank of an engine moves six times as far while the 
piston is travelling the first inch of the stroke as while it 
is making the middle inch, and a little over twice as far 
while the piston is moving the second inch, and a trifle 
over li times as far while the piston moves the third 
inch, and the fourth inch less than I J times as far. The 
crank also travels less when the piston is making the last 
inch of the stroke than it does while it is making the 
first. 

An explanation of the objections formerly urged against 
the employment of the crank as a means of converting a 
reciprocating into a rotary motion, namely, that its leverage, 
and therefore its power, is so variable, will be found under 
the head of Cranks, page 109. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



81 



TABLE 

SHOWING THE POSITION OF THE PISTON IN THE CYLINDER AT 
DIFFERENT CRANK ANGLES, ACCORDING TO THif LENGTH OF CON- 
NECTING-ROD. 

(For Back-action Engines, the words " Forward " and '* Return " must be reversed.) 





Length of 


Length 


of 1 


Length of 




Conneeting-Rod 


Connecting-Rod 


Connecting-Rod 




4 to 1 of Stroke. 


4}4 to 1 of Stroke. 


5 to 1 of Stroke. 


Piston Position 




















in Cylinder. 


t . 






'Ho- 


^ 




V. . 








ej a> 


£ o 




03^ 


t; '^ 




« o 


S <^' 






Deg. 


qM 




fe O 


3^ 




k:M 


^M 






Deg. 


ft 
Deg. 


^±3 


5 o 


s 

Deg. 


1^ 




5tt 
Deg. 




Deg. 


Deg. 


Deg. 


Deg. 


0.125 =r| 


37| 


46:1 


91 


371 


46} 


8| 


371 


45f 


7| 


0.2 


48 


59^ 


llj 


481 


58f 


10^ 


48| 


58i 


9f 


0.25 = J 


54| 


66| 


12| 


54| 


66 


Hi 


55| 


65f 


10 


0.3 


60 


73| 


13 


61 


72| 


111 


61i 


72 


lOJ 


0.333 =- i 


64i 


771 


13f 


64| 


76i 


12i 


65| 


76} 


10^ 


0.375 = 1 


QSi 


82f 


13J 


691 


82 


12J 


70} 


81f 


114 


0.4 


71f 


85f 


13J 


72f 


84f 


12i 


73 


84} 


11} 


0.45 


77i 


91J 


l4i 


781 


901 


12^ 


781 


90 


111 


0.5-:J 


821 


97- 


14} 


83f 


96} 


12J 


84f 


951 


Hi 


0.55 


88^ 


102| 


14i 


891 


lOli 


12J 


90 


lOlf 


111 


0.6 


94| 


108} 


13i 


951 


107| 


12J 


95f 


107 


11} 


0.625 = f 


97} 


lllj 


13i 


98 


110^ 


12J 


98| 


1091 


IH 


0.65 


100} 


1138 


13| 


1011 


113^ 


12i 


101| 


1121 


lOi 


0.666 = f 


102| 


llSf 


13f 


1031 


1154 


12* 


103f 


114| 


101 


0.68 


104 


1171 


13| 


104f 


116i 


12 


105i 


116} 


10| 


0.7 


1061 


1191 


13 


107f 


119 


111 


108 


118J 


10| 


0.71 


107i 


120i 


121 


108f 


120} 


111 


109f 


1191 


101 


0.73 


llOJ 


123} 


12| 


111} 


1221 


Hi 


112 


122i 


lOJ 


0.75 = f 


113} 


1251 


12| 


114 


125i 


ni 


114| 


1241 


10 


0.76 


1141 


1261 


12i 


1151 


1261 


11 


116i 


125J 


9| 


0.77 


1161 
117| 


1281 


12 


116i 


1271 


lOf 


117^ 


127} 


9| 


0.78 


1291 


llf 


118f 


1281 


10^ 


119 


128^ 


9^ 


0.79 


1198 


1301 


111 


119J 


130} 


lOf 


120 J 


129f 


9} 


0.8 


120^ 


132 


Hi 


121} 


131i 


lOi 


1211 


13H 


9} 


0.81 


122i 
1231 


133} 


iH 


122| 


132| 


10 


123J 


132J 


9 


0.82 


1341 


11 


1241 


134} 


91 


125 


133| 


8f 


0.83 


125f 


136 


lOf 


126 


135| 


91 


126f 


135J 


8| 


0.84 


127 


137J 


10^ 


1271 


137 


91 


128} 


136t 


8^ 


0.85 


1281 


138J 


m 


1291 


138J 


9J 


130 


138} 


8} 


0.86 


130i 


1401 


n 


131} 


140 


8f 


131 1 


1391 


84 


0.87 


132| 


142 


9| 


133 


141f 


8t 


133| 


141r 


71 


0.875 = 1 


133}142f 


9-^ 


133| 


1421 


8i 


134i 


142J 


71 



F 



82 



HAND-BOOK OF LAND AND MARINE ENGINES. 



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HAND-BOOK OF LAND AND MARINE ENGINES. 83 

PISTON-RODS. 

Piston-rods, like valve-, eccentric-, and connecting-rods, 
are subjected to different strains, such as compression, 
tensile or pull, and bending ; the latter is most sensibly 
felt in the case of engines out of line ; consequently, this 
detail should possess sufficient strength, without extra 
weight of material, to resist any shock to which the engine 
may be subjected. Piston-rods are generally wrought-iron, 
though steel is frequently used, and is very much superior 
to the former material, not only on account of its great 
strength and diminished friction, but that it is less liable 
to become grooved by the action of the packing. 

Piston-rods are in some cases connected with the cross- 
head by means of a screw and jam-nut ; but this method 
of attachinent is objectionable, and should never be re- 
sorted to when a key can be used ; although recently some 
very important improvements have been made in the 
former mode of attachment. 

CRANK-PINS. 

The crank-pin being that part of the engine by which 
the useful effect of the steam acting against the piston is 
converted into work, therefore its proper proportions are 
of interest and importance, and should receive due con- 
sideration from the designing engineer. 

Crank-pins have a tendency to become hot, because the 
work absorbed by the friction of the bearing is changed 
into heat. But this tendency to heat is independent of 
its diameter, it being only necessary to provide sufficient 
area to dissipate the heat stored up by the friction. 'The 
bearing upon a crank-pin is less than the projected area 
of the pin, consequently, the length of the pin that bears 



84 



HAND-BOOK OF LAND AND MARINE ENGINES. 



should always be used in calculating the proper pro- 
portions. 

Crank-pins are generally made of wrought-iron, though 
steel is frequently used, as it possesses many advantages 
over the former material, among which are strength, dura- 
bility, and diminished friction ; its first cost is greater than 
that of iron, but in point of economy it is much cheaper. 

Under the influence of the connecting-rod, the piston is 
placed in advance of its progress, due to the crank, 
throughout the front stroke, and is behind its due position 
at all parts of the back stroke. 

TABLE 

SHOWING THE ANGULAR POSITION OF THE CRANK-PIN CORRE- 
SPONDING WITH THE VARIOUS POINTS IN THE ST:^KE WHICH 
THE PISTON MAY OCCUPY IN THE CYLINDER. 



Piston 


Crank 


Piston 


Crank 


Piston 


Crank 


Position. 


Angle. 


Position. 


Angle. 


Position. 


Angle. 




De^. 




Deg. 


1 


Deg. 


0.1 


361 


0.5625 = ^\ 


97i 


0.813 = 11 


128^ 


0.125 = 1 


411 


0.575 


981 


0.82 


1291 


0.15 


45f 


0.6 


lOU 


0.83 


13U 


0.175 


49i 


0.625= 1 


104i 


0.84 


132i 


0.2 


53^ 


0.65 


107i 


0.85 


1341 


0.225 


56^ 


0.666 = f 


109i 


0.86 


136i 


0.25 = i 


60 


0.68 


IIU 


0.87 


1371 


0.275 


631- 


0.687 =H 


112 


0.875 = i 


138f 


0.3 


661 


0.69 


1121 


0.88 


139t^ 


0.325 


69i 


0.7 


113§ 


0.89 


141i 


0.333 = i 


70^ 


0.71 


114i 


0.9 


143i 


0.35 


72i 


0.72 


ll6i 


0.91 


145i 


0.375 


75i 


0.73 


im 


0.92 


147i 


0.4 


78i 


0.74 


1181 


0.93 


1491 


0.425 


811 


0.75 = 1 


120 


0.94 


15U 


0.437=3^ 


82^ 


0.76 


1211 


0,95 


154^ 


0.45 


m 


0.77 


122t 


0.96 


156^ 


0.475 


87^ 


0.78 


124i 


0.97 


im 


0.5 = i 


90 


0.79 


125i 


0.98 


1631 


0.525 


921 


0.8 


126^ 


0.99 


168i 


0.55 


951 


0.81 


128i 


1.00 


180 



HAND-BOOK OF LAND AND MARINE ENGINES. 85 

STEAM-CHESTS. 

The steam-chest should be made as small ias possible, 
in order to avoid radiation of heat, weakness, and large 
joints ; but it must contain ample room for valve adjust- 
ment, and for the passage of the full volume of steam re- 
quired in the cylinder from one end to the other as the 
valve moves. It should also be of sufficient length to ad- 
mit of extra lap being added to the valve, if necessary. 

VALVE-RODS. 

Valve- rods, like connecting- and eccentric-rods, are 
subject to certain strains, among which are, most sensible 
compression, and tensile or pull. They are most generally 
made of wrought-iron ; but, like piston-rods, when made 
of steel, are much more durable, and less liable to spring 
or become fluted by the action of the packing. 

Length of Valve-rods.— -To find the proper length of 
valve-rods, place the valve centrally over the ports, and 
the rocker or intermediate bearings in a perpendicular 
position ; then the length of the valve-rod can be accu- 
rately determined by measuring from the centre of the 
rocker-stud to the centre of the valve. 

GUTOES. 

The guides of steam-engines embrace a great variety 
of designs and forms, and, as there is no rule which would 
apply to the guides of all classes of engines, consequently, 
in fixing their strength, as in many other details of the 
steam-engine, we must be governed entirely by practice ; 
but they should be made of sufficient strength to prevent 
the possibility of springing at any speed to which the 
engine might be subjected. The strain on the guides 
8 



86 HAI^J^D-BOOK OF hANB AND MARINE ENGINES. 

varies in differently connected engines, as with short con- 
nected engines it is very severe ; while with those having 
long connections it is but little more than the weight of 
the cross-head and connecting-rod. 

The strength op stiffness of guides depends more on 
design and shape, than on the quantity of material em- 
ployed, as, by a proper distribution of the metal, they can 
be made sufficiently strong without being extra heavy. 
The form of guides in most general use are the V shaped, 
round, and flat ; but the latter possesses many advantages 
over any other form, as they can be made more cheaply, 
and are less difficult to renew or repair. 

Guides are sometimes cast solid with the bed-plate; this 
arrangement answers very well for vertical engines, but 
for horizontal engines, it is decidedly objectionable, and 
cannot be advocated on any other grounds except that of 
economy, as they are impossible to readjust and very 
difficult to renew. 

ROCK-SHAFTS. 

The diameter and length of the rock-shaft bearing de- 
pend somewhat on the construction of the engine ; if long 
and subjected to torsion, or working an unbalanced slide- 
valve, the diameter should be from i to i the diameter of 
the engine-shaft; if not subjected to torsion, i the diameter 
of the engine-shaft will do. 

Rook-shaft Pin.— The diameter of the rock-shaft pin 
should not be less than the valve-stem ; but if an over- 
hanging pin, it should be from li to 1} the diameter of 
the valve-stem. 

CROSS-HEADS. 

The form of the cross-head, like many other details of 
the steam-engine, is influenced by the circumstances of 



HAND-BOOK OF LAND AND MARINE ENGINES. 87 

design and construction ; but the most essential requisite 
of the cross-head is, that it should possess sufl3.cient strength 
to resist the strains transmitted from the moving mass, and 
also have ample bearing on the guides to prevent the pos- 
sibility of rapid wear or excessive friction. 







STEAM-PORTS. 

The dimensions of the steam-ports rank next in im- 
portance to the cut-off in their controlling influence upon 
the proportions of the valve-seat and face. They may 
justly be considered as a base, from which all the other 
dimensions are derived in conformity with certain me- 
chanical laws. 

Their value depends greatly upon the manner in which 
the ports are employed, whether simply for admitting the 
steam to the cylinder, or for purposes both of admission 
and escape. 

In case of admission, if the port is properly designed, 
it is evident that the pressure will be sustained at substan- 
tially a constant quantity by the flow of steam from the 



88 



HAND-BOOK OF LAND AND MARINE ENGINES. 



boiler. But with the exhaust the ease is different, as the 
steam is forced into the atmosphere with a constantly di- 
minishing pressure and less velocity. 

When a small travel of the valve is essential, the length 
of the port should be made as nearly equal to the diameter 
of the cylinder as possible. 

The ports of long-stroke slide-valve engines should be 
located as near the ends of the cylinder as possible, in 
order to reduce the cubic contents of the passages, as at 
each stroke of the engine the contents of long passages 
are thrown away, without producing any effect except to 
increase the volume of the exhaust. By locating the ports 
near the end^ of the cylinder, the steam is admitted with 
a higher pressure than if the passages were long. 

TABLE 

SHOWING THE PROPER AREA OF STEAM-PORTS FOR DIFFERENT 
PISTON SPEEDS. 



Speed of Piston. 


Port Area. 


Speed of Piston. 


Port Area. 


Feet per Minute. 
200 
250 
300 
350 
400 


Area of Piston. 
.04 
.047 
.055 
.062 
.07 


Feet per Minute. 
450 
500 
550 
600 


Area of Piston. 
.077 
.085 
.092 
.1 



Having decided the relative area that the ports should 
bear to the cylinder area, it is next necessary to resolve it 
into its proper factors of diameter, or length and width. 
For instance, if the steam cylinder be 20 inches in diameter, 
and the port area be y^g the area of the cylinder, if the 
valve be poppet or conical, the diameter of the steam- 
ports will require to be 5 inches ; or, if proportioned for a 
slide-valve, for the diameter of cylinder and the same pro- 



HAND-BOOK OF LAND AND MARINE ENGINES. 89 

portionate area of port, it would need to be 15| inches 
long by I4 inches wide. 

Ports should be made as straight and direct as the cir- 
cumstances of design and construction will permit ; it is 
also desirable that their surfaces should be as smooth as 
possible. 

SLroE-VALVES. 

The slide-valve is that part of the steam-engine which 
causes the motion of the piston to be reciprocating. It is 
made to slide upon a smooth surface, called the valve-seat, 
in which there are three openings — two for the admission 
of steam to the cylinder alternately, while the use of the 
third is to convey away the waste steam. The first two 
are,' therefore, termed the steam-ports, and the remaining 
one the eduction- or exhaust-port. 

Probably no part of the steam-engine has been the sub- 
ject of more thought and discussion than the slide-valve. 
Its proportions have been discussed in elaborate treatises, 
and its movements and functions analyzed by profound 
mathematicians, with the aid of the most extensive formu- 
las and calculations ; and yet, notwithstanding all these 
investigations, any one who undertakes to study its action, 
will find it difficult to discover anywhere a full or satisfac- 
tory explanation of the whole subject. 

If some of our learned professors would instruct engi- 
neers how to design and construct a slide-valve that would 
give better results, under the varying circumstances to 
which slide-valves are subjected, than any now in use, it 
would do more to make them familiar with the principles 
involved in the construction and working of the slide- 
valve than any geometrical solution of its movements that 
might be given, however learned, as such theories are but 
very imperfectly understood by engineers in general. 
8^ 



90 



HAND-BOOK OF LAND AND MARINE ENGINES. 



I 



In examining the special application of the slide-valvej 

to the steam-engine, it will be necessary to consider- what 
the requirements of the engine are ; for the valves, of 
whatever kind, being to that machine what the lungs are 
to the body, must necessarily be so actuated as to regulate i 
the admission and escape of the steam, which is its breath, I 
in accordance with the conditions imposed by the motion 
of the piston. 

The valve may be said to be the vital principle of the 
engine. It controls the outlet to the coal and wood pile. 
It is, therefore, of the highest importance that it should 
work practically under all circumstances. 

Now the admission of steam is one thing and its escape 
is another, and though both may be regulated by what is 
called one valve, because it is made in one piece, yet this 
is not by any means necessary. Four separate valves may 
be, and sometimes are, employed in stationary engines, — a 
steam- and an exhaust- valve at each end of the cylinder ; 
but the functions of all these are distinctly performed by 
the common three-ported slide-valve. j 




Position of the Slide-valve when in the Centre of its Travel. 

It is evident that the admission cannot continue longer, 
in any case, than the stroke does, so that by the time that 
is completed, the valve must have opened and closed the 
port. These conditions determine the modification of the 
movement which must be used, and the greatest breadth of 
the port for any assumed travel of valve. 

When the motion of a slide-valve is produced by 



HAND-BOOK OF LAND AND MARINE ENGINES. 91 

means of an eccentric, keyed to the crank-shaft and revolv- 
ing with it, the relative positions of the piston and slide- 
valve depend upon the relative positions of the crank and 
eccentric. 

The greatest opening of the port is half the travel of 
the valve ; in this case the steam is admitted during the 
whole stroke of the piston, at the beginning of which the 
valve, which has no lap, is at the centre of its travel. 

If the eccentric be so placed that at the beginning of 
the stroke of the piston the valve is not at the centre of 
its travel, the opening of the port will be reduced, and it 
will be closed before the piston completes its stroke. 

In this case, the opening of the port will be less than 
half the travel, by as much as the valve, at the beginning 
of the stroke of the piston, varies from its original central 
position. And when the valve is at half-stroke, it will 
overlap the port on the opening edge to the same extent. 

The point in the stroke of the piston at which the port 
will be closed and the steam cut off, will depend upon the 
angular position of the eccentric at the beginning of the 
stroke. 

When the valve is so formed that, at half-stroke, the 
faces of the valve do not close the steam-ports internally, 
the amount by which each face comes short of the inner 
edge of the port is known as inside clearance. 

From the nature of the valve motion, it follows that the 
distribution is controlled by the " outer and inner edges of 
the extreme-ports and of the valve." The mere width of 
the exhaust-port or thickness of bars is immaterial to the 
timing of the distribution. 

The extreme edges of the steam-ports and those of the 
valve regulate the admission and suppression ; and the 
inner edges of the ports and the valve command the re- 
lease and compression. 



92 



HAND-BOOK OF LAND AND MARINE ENGINES. 



Fop every stroke of the piston, four different events 
occur — the admission, the suppression, the release, and the 
compression. 

The advance of the valve denotes the amount by which 
the valve has travelled beyond its middle position, when 
the piston is at the end of the stroke, and is known as 
linear advance. 

The slide-valve is more wasteful of steam than the pop- 
pet, or other forms of valve, in consequence of the long 
ports necessary to its use ; but even with this defect, it must 
be conceded that nothing has as yet been introduced that 
has so well answered the purpose of controlling the induc- 
tion and eduction of the steam to and from the cylinder as 
the slide-valve. 




Position of tlie Slide-valve when the Crank is at the " Dead Centre," 



When correctly designed and well-made, the slide- 
valve is one of the simplest and most effective devices 
ever invented for its office ; and, on account of its simplicity 
of form, durability, and positive action, it has been able to 
successfully compete with all other forms of valves ; nor is 
it at all likely that it will ever be superseded by any other 
form for engines of moderate size, more particularly where 
high piston speed is an object. 

The friction of the slide-valve depends to a certain ex- 
tent on the distance traversed by the valve. Hence it is 
desirable to reduce the travel as much as possible, more 
especially in the case of large engines. This object can be 
accomplished by increasing the number of ports as shown 



HAND-BOOK OF LAND AND MARINE ENGINES. 



93 



in the accompanying cut ; so that one half the travel will 
be sufficient to give a full port area. 




Short Travel Slide-valves. 

PROPORTIONS OP SLIDE-VALVES. 

In order to show how to properly proportion a slide- 
valve, it will be necessary to give an example. 

Example. — Length of valve, 8^ inches; exhaust opening 
under valve, 4 inches; exhaust-port in face, 2| inches; 
inside bridge, | inches thick ; steam-ports, 1^ inches wide ; 
travel of valve, 4i inches ; lead j'g. These proportions give 
a one-inch lap on each side when the valve is in the middle 
of its travel ; the travel of this valve is 3*6 times the width 
of the port, which may be accepted as a good proportion 
for ordinary practice. 

LAP ON THE SLIDE-VALVE. 

The term " lap " is familiar to all steam engineers, as 
denoting those portions or edges of the working-faces of 
the valves which extend past or beyond the ports. The 
object of lap is to work the steam expansively ; as, when 
the valve has lap, it cuts off the steam supply to the piston 
before the latter has travelled to the end of the stroke ; 
without lap, there would be no expansion, because admis- 
sion and release would occur at the same time. 

Lap also induces an early and efficient release, because 
the lead of the exhaust, or the amount which the valve is 



94 HAND-BOOK OF LAND AND MARINE ENGINES. 

open to the exhaust at the end of the stroke, is increased 
by the amount of lap on the outside. 

Lap on the steam side is termed the outside lap, while 
lap on the exhaust side is known as inside lap. 

With a common slide-valve, it is not practicable to cut 
off the steam supply to the cylinder sufficiently early in 
the stroke to effect so large a degree of jxpansion as by 
some other means, because it would require the valve to 
have an excessive amount of outside lap, and the exhaust 
would take place too early in the stroke, thus causing the 
piston to travel a large proportion of the latter part of the 
stroke without having any pressure of steam behind it. 

Slide-valves work to better advantage when the lap is so 
proportioned as to cut off the steam at from two-thirds to 
three-quarters of the stroke, than at any other "point, be- 
cause of the comparatively long stroke of the valve when 
more lap is added, and the great amount of friction gen- . 
erated between the valve-face and its seat. 

The amount of inside lap is at all times to be governed 
by the speed at which the engine is to run, but it should 
never, in any case, be less than y^^ of an inch.. Fast- 
running engines might have inside lap equal to one-half 
the outside lap, while engines travelling at slow speeds 
might have a little more. 

The slide-valve is sometimes so proportioned as to give 
it inside clearance, that is, the exhaust cavity in the face 
of the valve is wider than the nearest edges of the steam- 
ports in the seat, so that, when the valve is placed centrally 
over the ports, there is a clear communication, to the ex- 
tent of the clearance, between each steam-port and the 
exhaust. The object of clearance is to give the valve a 
freer exhaust ; but this is a grave mistake, as, in propor- 
tioning a slide-valve, the inside extreme should never ex- 
ceed line and line. 



HAND-BOOK OF LAND AND MARINE ENGINES. 95 

Inside clearance in a valve having outside lap is an 
evil, as it increases tlie exhaust opening in addition to 
that given by the lead of the valve, and allows the steam 
to escape too early in the stroke to produce the effect that 
it would if the valve had a certain proportion of inside 
lap. 

POPPET OR CONICAL VALVES. 

On a poppet-valve, there cannot be any lap; but the 
same effect is obtained in engines of this character by so 
adjusting the eccentrics and the lifting toes, that the valves 
will be lowered into their seats at the right period, or at 
the time when the passages require to be closed to pro- 
duce the effect. The early closing of the steam-valves 
allows the steam to expand itself, and thereby to work 
with economy in the cylinder. The early closing of the 
exhaust -valves prevents the escape of the weak steam 
which is before the piston, and compresses it. 

By closing the exhaust- valves very early, this compres- 
sion may be carried to such an extent as to induce a press- 
ure equal, or even superior, to that in the boiler. It is 
never desirable, in engines of this character, to " compress " 
to this extent, but by judiciously closing the exhaust-valves, 
and producing a gentle compression, an effect somewhat 
equivalent to '4ead" is produced. In some engines, this 
compression is substituted for lead altogether, and the pis- 
ton, at the moment of commencing its stroke, is only 
actuated by the steam which has been thus imprisoned. 

This mode of operating works very economically, be- 
cause it tends to save the steam, which would otherwise be 
required to fill the valve-passageg and the little space at 
the end of the cylinder generally known as the " clear- 
ance." In other words, the steam, on flowing in at the 
commencement of the stroke, usually has to fill up a cer- 



96 HAND-BOOK OF LAND AND MARINE ENGINES. 

tain amount of empty space at the end of the cylinder 
before it begins to act with its proper effect upon the pis- 
ton; but when this space has been previously filled to 
some extent, by the compression above described, a smaller 
quantity of steam is required to be drawn from the boiler 
for this purpose. In the Corliss engine, and some others 
in which the valves are opened and closed very rapidly, 
this mode of working is almost invariably practised. 

Lift of Conical op Poppet Valves. — The required lift 
of conical or poppet-valves to give an opening equal to the 
area of the port is one-half the radius, or one-quarter of the 
diameter, which can be explained as follows : If a cylinder 
be drawn, whose height equals one-fourth its diameter, the 
convex surface of such a cylinder is just equal to the area of 
the circle of the cylinder. From this it is evident that if 
a circular valve of any diameter lifts from its seat a dis- 
tance equal to one-fourth its diameter, the area of the open- 
ing round it will equal the area corresponding to its diam- 
eter. 

Ru\e for finding the Required Amount of Lap for a Slide- 
valve corresponding to any desired Point of Cut-off, — From 
the length^f stroke of piston, subtract the length oLlhe 
stroke that is to be made before the steam is cut off; 
divide the remainder by the stroke of the piston, and 
extract the square root of the quotient. Multiply this 
root by half the throw of the valve ; from the product 
subtract half the lead, and the remainder will give the 
lap required. 

Another Rule. — Multiply the given stroke of the valve 
by the decimal numbers under each point of cut-off. 

Pnf r^ff* 1 "7 2 3 5 7 11 

uut-on, 2 TU 3 4 5 S i^ 

Multiplier, -354 -323 '289 -250 -204 -177 -144 



HAND-BOOK OF LAND AND MARINE ENGINES. 97 

TABLE 

SHOWING THE AMOUNT OF " LAP " REQUIRED FOR SLIDE-VALVES 
OF STATIONARY ENGINES WHEN THE STEAM IS TO BE WORKED 
EXPANSIVELY. 

The travel of the valves being ascertained, and also the 
amount of cut-off desired, the following table shows the 
amount of "lap." For instance, if a valve has ^ lap, it 
will overlap each steam-port | of an inch when in the 
centre of its travel. 



Travel of 
the Valve 
in Inches. 


The Travel of the Piston where the Steam is 


cut off. 




i 


i 


ft 


1 


ft 


1 


f 


if 






















The required * 


' Lap." 






2 


i 


i 


H 


1 


ft 


J 


tV 


f 


2i 


IrV 


1 


i 


il 


H 


ft 




ft 


3 


U 


ift 


i| 


1 


tI 


1 


1 


ft 


3J 


l| 


ift 


Ift 


li 


Ift 


1 


F 


f 


4 


If 


ift 


Ift 


1ft 


li 


1ft 




H 


4J 


2 


m 


Ift 


u 


Is 


li 


1 _ 


i 


5 


2J 


2 


i-H 


1ft 


1* 


If 


1 J 




5^ 


2ft 


2ft 


2 


m 


ll 


u 


1 


U 


6 


2J 


2ft 


2ft 


2 


HI 


If 


J i 


Ift 


61 


2| 


2ft 


2ft 


2/t 


2 


Hi 


I \ 


H 


7 


3 


m 


2ft 


2| 


2ft 


2 


1 f 


U 


7i 


3ft 


3 


m 


2 J 


2f 


2ft 


I ¥ 


1 J 


8 


3ft 


3ft 


3 


2f 


2* 


21 


2 


■*■ 8 


^ 


3f 


3ft 


3ft 


2if 


2i|- 


2i 


2i 




9 


311 


3| 


3ft 


3 


2« 


2H 


2i 


l¥ 


9J 


4 


3H 


3t 


3ft 


3 


2tI 


2« 


2 


10 


4i 


4 


3U 


3ft 


3ft 


3 


2i 


2A 


m 


4ft 


41 


4 


Si 


3ft 


li 


2| 


11 


4ft 


4ft 


4i 


3f 


3i 


2i 


2i 


Hi 


4}-J 


4ft 


4ft 


31 


3f 


3f 


2i 


2 - 


12 


5 


4r* 


4ft 


4| 


4 


3f 


3 


2I 



LEAD OP THE SLIDE-VALVE. 

The object of the lead is to enable the steam to act as 
a cushion against the piston before it arrives at the end 
of the stroke, and cause it to reverse its motion easily ; and 
9 G 



98 h4lND-book of laistd and maiii:n^e engines. 

also to supply the steam of full pressure to the piston from 
the instant it has passed its dead centre. 

When the work an engine has to perform is very irregu- 
lar, as is generally the case in rolling-mills, or if the 
different parts of the engine be badly worn or have much 
lost motion, considerable lead is absolutely necessary, in 
order that the steam admitted will offer an opposing and 
gradual force in a direction opposite to that in which the 
engine is moving, and take up the play in the different 
parts before the piston has reversed its motion. 

If the piston, after passing the centre, should meet with 
no opposing force, it would travel very fast during the 
time in which the play was being taken up, and, when the 
valve opened again, it would receive a check from the 
action of the steam which would cause it to thump or 
pound. 

j Lead, like many other details, requires the exercise of 

mechanical skill and judgment, as, if a valve has too much 

ilead, not only is there a great loss of power, but the piston 

/receives a violent shock at each end of the stroke, and it 

1 will be found almost impossible to keep the packing tight 

s around the pistou-rod in consequence of the excessive 

cushioning. 

If the amount of lead be so great as to admit steam of 
the full pressure to the passages and clearance, the piston 
will have to force it back into the passages and chest, ex- 
posing the wrist- and crank-pins to a fearful shearing 
strain when the crank is at its w^eakest point — the fly- 
wheel travelling fast and the piston moving very slowly. 

No general rule can be given for the amount of lead 
that would be best suited or most advantageous for all 
classes of engines, as that must be determined by the 
circumstances of construction, speed, work, etc. 
i In the case of vertical engines having the cylinder 



HAND-BOOK OF LAND AND MARINE ENGINES. 99 

above and the crank below, it is customary to give less 
lead on the upper than on the lower port, as the wear in 
the valve connections has a tendency to increase the lead 
on the upper end. With vertical engines having the 
crank above and the cylinder below, these conditions are 
reversed. It is also customary in the case of horizontal 
engines to give more lead on the front than on the back 
end, in consequence of the reduced capacity cf that end 
arising from the space occupied by the piston-rod. 

Fop stationary engines, the lead varies in general prac- 
tice from ^\ to j\ of an inch ; the exhaust lead being in 
all cases double the amount of ^steam lead. 

The average amount of lead, in full gear, for freight 
locomotives, is j\ of an inch ; for locomotives running ac- 
commodation passenger trains, j\ of an inch ; and fast 
express locomotives, ^\ of an inch. 

CLEARANCE. 

The term clearance is used to express the extent of the 
space which exists between the piston, the cylinder-head, 
and the valve-face at each end of the stroke. For each 
stroke of the piston, this space must be filled with steam, 
which in no way improves the action of the engine, but 
rather increases the amount of steam to be exhausted on 
the return-stroke. , 

It is, therefore, an object of great importance, in point 
of economy, to have the valve-face as near the bore of the 
cylinder as possible, in order that the cubic contents of the 
space in the cylinder unoccupied by the piston and the 
steam passages may be reduced to their smallest capacity. 



100 HAND-BOOK OF LAND AND MARINE ENGINES. 

COMPRESSION. 

Compression is the term used to express the distance 
the piston moves in the cylinder after release or exhaust 
has taken place, and the exhaust passage closed by the 
return-stroke of the valve, whereby the communication 
is cut off from the exhaust-port and that end of cylinder. 
Compression takes place between the piston and cylinder- 
head at each end of the stroke, and the distance from the 
end of the cylinder at which it takes place depends on the 
amount of lap on the valve. 

FRICTION OP SLIDE-VALVES. 

All engineers agree that there is a great loss of power in 
working the slide-valve, but differ in the amount, from the 
fact that no correct data has been formed by which to 
make such calculations ; but an idea has been very gener- 
ally entertained by engineers, that the number of square 
inches in a slide-valve, and the pressure of steam in pounds 
per square inch, represented the total pressure on its back, 
or that the pressure was equal to the pressure of steam 
per square inch on the back of a valve minus the area of 
the steam-ports. 

Such conclusions, however, are erroneous, as the num- 
ber of square inches in a slide-valve, and the pounds 
pressure per square inch, would only represent the weight 
on its back, if we consider the valve as a solid block of 
iron with a smooth surface, resting on a smooth solid 
bearing perfectly steam-tight, as then the steam would 
press on every square inch of surface with the same force 
that a dead weight laid upon it would. 

These conditions are never found in a slide-valve ex- 
cept in one position — that one, when the valve overlaps 



HAND-BOOK OF LAND AND MARINE ENGINES. 101 

both ports, and the engine is at rest. As soon, however, 
as the valve is moved, the steam enters the open port, and 
the pressure is practically taken off that end of it. 

When the valve is moved back over the port, the steam * 
that is shut up within the cylinder will press up against 
the under side of the valve-face with a force exactly equal 
to the pressure at th^ point in the stroke of the piston 
at which the valve closed. 

As the valve continues its stroke, the other port will be 
opened, and the steam that was shut up in the cylinder 
begins to exhaust ; and the pressure against the under side 
of the valve will be the same as the pressure in the cyl- 
inder at the end of the stroke. This pressure is only for 
a brief period, for in engines with well-proportioned steam- 
ports, the time occupied in exhausting the contents of the 
cylinder is very short. * 

While the steam is entering the open port, and after the 
exhaust has passed through the closed port, the pressure 
on the under side of the valve will be just the ordinary 
back pressure. 

Therefore, in order to determine the pressure on a slide- 
valve, we must consider the pressure in the cylinder at 
the time of cutting off the back pressure against the piston, 
the area of the ports, etc. 

Rule for finding the Pressure on Slide-valves. — Mul- 
tiply the unbalanced area of the valve in inches by the 
pressure of steam in pounds per square inch; add the 
weight of the valve in pounds, and multiply the sum by 
0-15. 

Another Rule.— Multiply the combined area of the 
bearing surface and ports' in inches by the steam pressure 
in pounds per square inch on the back of the valve ; mul- 
tiply this product by the coefficient of friction between the 



102 HAND-BOOK OF LAND aItD MARINE ENGINES. 

two surfaces.* The product will be the force required to 
move the valve when unbalanced. 

BALANCED SLIDE-VALVES. 

The mechanical difficulties heretofore experienced in 
producing a balanced slide-valve that would be reliable 
under all the varying circumstances to which slide-valves 
are exposed, have not, so far, been fully overcome, as may 
be inferred from the views of the American Railway 
Master Mechanics, expressed at their last annual conven- 
tion at Chicago. Their discussions on this subject were of 
great importance, and embraced a wider range of expe- 
rience than any other equal number of mechanics in this 
country. While they all agreed that the use of balanced 
slide-valves on locomotives would be of great benefit, as 
they wt)uld materially diminish the wear of valve gear ; 
they were almost unanimously of the opinion that not one 
of the balance valves now in use on locomotives was per- 
fectly reliable, as they were all open to the objection of 
leaking, and the expense incurred by the use of the un- 
balanced valve was less than that of keeping the balance 
valve in repair. 

The pemoval of the weight from the back of the valve 
would be a step in the right direction, and, as the attention 
of engineers and railway mechanics is directed that way, 
and the difiiculty does not appear to be insurmountable, it 
is not at all improbable that some of the different forms 
of balance valves now in use will be so modified and im- 
proved as to accomplish the desired object. 

There are many forms of the balance valve that have 
rendered good service, but none of them have, so far, idet 
all the requirements of a good steam-tight slide-valve. 

* See Table of Coefficients, pages 480, 481. 



HAND-BOOK OF LAND AND MAKINE ENGINES. 103 

PITTING SLIDE-VALVES. 

The accurate fitting of the slide-valve to its seat 
requires the closest attention on the part of the engineer 
and machinist ; yet these very important details are very 
often neglected under the impression that the valve will 
wear down to a steam-tight bearing, or, in other words, 
find its own seat. 

But experience has shown this to be a very erroneous 
idea, as improperly fitted valves frequently commence to 
wear out of shape from the first time they are used, and 
the extra expense incurred in replacing them frequently 
amounts to three times as much as it would have cost to 
make a thorough fit in the first place. 

SLIDE-VALVE CONNECTIONS. 

The most ordinary methods of connecting the slide- 
valve are by means of an oblong hole in the back of the 
valve, through which the rod is slipped and secured at 
each end by jam-nuts ; or by a single nut resting in a recess 
formed in the back of the valve ; or, as in the case of the 
locomotive, by means of a yoke which encircles the valve ; 
the latter mode forms the most permanent attachment, 
particularly for large engines, as the jam-nuts, though 
afibrding the best facilities for adjustment, are objection- 
able on account of their liability to become loose and wear 
the stem ; the single nut, unless thoroughly fitted^ is open 
to the same objection. 

It is no uncommon thing to find well-proportioned and 
well-fitted slide-valves, only a short time in use, worn 
rounding on the face in consequence of the vibration or 
springing of defective connections. 



104 HAND-BOOK OF LAND AND MARINE ENGINES. 




ECCENTRICS. 

The term " eccentric " is applied to all such curves as 
are composed of points situated at unequal distances from 
a central point or axis. 

The motion imparted to the slide-valve is generally 
derived from two principles of action — vibratory and 
rotary. When the former is the prime mover, the speed 
of the valve is the same throughout the stroke ; or rather, 
if the motion is imparted by the piston, the motion of it 
and the valve would be equal. 

Rotary motion is more often adopted than any other 
for the transmission of power and action, and at present, 
small cranks and eccentrics are the prevailing means 
employed to impart the motion required for the slide- 
valve. The speed of the crank and the eccentric are pro- 
portionately the same in theory and practice. 

Upon inspection, it will be seen that the eccentric is 
only a mechanical subterfuge for a small crank. This 
being so, a crank of the ordinary form may, and frequent- 



HAND-BOOK OF LAND AND MARINE ENGINES. 105 

ly is, used instead of an eccentric — the latter being a 
mechanical equivalent introduced, because the use of the 
crank is, for special reasons, inconvenient or impracti- 
cable. 

Since the shaft to which the eccentric is fixed makes 
a half revolution while the piston is making one stroke, 
it follows that whatever device may be used for converting 
the reciprocating motion of the piston into rotary motion, 
the slide-valve may be actuated by an eccentric fixed on 
any shaft which makes a half revolution at each stroke of 
the piston. 

It will now be observed that the eccentric and valve 
connection is nothing more nor less than a small crank 
with a long connecting rod ; the valve will therefore move 
in precisely the same manner as the piston, and will have, 
in its progress from one extremity of the travel to the 
opposite, like irregularities. 

In other words, when the eccentric arrives at the posi- 
tions for cut-ofi* and lead, the valve will be drawn beyond 
its true position — measured towards the ^ecentric — by a 
distance dependent on the ratio between the throw of the 
eccentric and the length of its rod. 

When the eccentric stands at right angles to the crank, 
the exhaust closes and release commences at the extremities 
of the stroke; consequently, if the eccentric be moved 
ahead 30°, not only will the cut-oQ* take place 30° earlier, 
or at a crank-angle of 120° instead of 150°, but the release 
will take place 30° earlier, or at the 150° crank-angle. 

Fop a cut-off, say of 140°, there would be required an 
angular advance of 20°, and a lap equivalent to the dis- 
tance these degrees remove the eccentric centre from the 
line at right angles to the crank ; for a cut-off* of 160°, an 
advance of 10°, with a corresponding lap, and so on, the 
exhaust closure taking place respectively at the 160° and 
170° crank-angles. 



106 HAND-BOOK OF LAND AND MARINE ENGINES. 

This closure of the exhaust confines the steam in 
cylinder until the port is again opened for the returi 
stroke ; consequently, the piston in its progress will meet^ 
with increasing resistance from the steam, which it thus 
compresses into a less and less volume. 

Such opposition, when nicely proportioned, aids in over- 
coming the momentum stored up in the reciprocating parts 
of the engine, and tends to bring them to a uniform state 
of rest at the end of each stroke. 

Since the closure of one port is simultaneous with the 
opening of the other, a release will take the place of the 
steam which was previously impelling the piston* 

Within certain limits an early release is productive of 
a perfect action of the parts, for an early release enables a 
greater portion of the steam to escape before the return 
stroke commences; whereas, a release at the end of the 
stroke would be attended by a resistance of the piston's 
progress, from the simple fact that steam cannot escape 
instantaneously through a small passage, but requires a 
certain definite portion of time, dependent on the area of 
the opening and the pressure of the steam. 

Angular Advance. — By angular advance is meant the 
angle at which the eccentric stands in advance of that 
position which would bring the slide-valve amid stroke, 
when the crank is at the dead centres. 

Throw or Stroke of the Eccentric. — The throw of the 
eccentric is twice the width of one steam-port, with twice 
the amount of lap on one side of the valve added. 

How to find the Throw of any Eccentric. — Measure the 
eccentric from the shaft, on the heavy and light sides; 
the difference between the two is the throw. 

Eccentrics of Marine Engines. — Eccentrics of marine 
engines are generally made in two pieces and bolted to- 
gether, and, when only a single eccentric is used, are 



HAND-BOOK OF LAND AND MARINE ENGINES. 107 

always loose on the shaft. The eccentric is fitted on the 
shaft so that it can move half-way round ; there are two 
stops on the eccentric and one on the shaft. The shaft 
revolves without the eccentric until it has moved a half 
revolution, when the pin on the shaft comes in contact 
with one of the stops on the eccentric, and moves it for- 
ward in the direction of the motion. 

When it becomes necessary to reverse the engine, the 
engineer notices whether the piston is moving up or down ; 
if moving up, he takes the starting-bar, throws the eccen- 
tric-hook out of gear, and admits steam to the top of the 
piston, which immediately changes the motion of the engine ; 
and when the shaft has moved around a half revolution, 
the stop on the shaft comes in contact with the second 
stop on the eccentric, and reverses its position on the 
shaft. 

Formula by which to find Positions of Double Eccentrics 
on the Shaft. — Draw upon a board two straight lines at 
right angle to each other, and from their point of intersec- 
tion as a centre describe two circles, one representing the 
circle of the eccentric, the other the crank-shaft ; draw a 
straight line parallel to one of the diameters, and distant 
from it the amount of lap and lead ; the points in which 
this parallel intersects the circle of the eccentric are the 
positions of the forward and backing eccentrics. 

Through these points draw straight lines from the centre 
of the circle, and mark the intersection of these lines with 
the circle of the crank-shaft ; measure with a pair of com- 
passes the chord of the arc intercepted between either of 
these points and the diameter which is at right angles with 
the crank, the diameters being first marked on the shaft 
itself; then by transferring with the compasses the dis- 
tances found in the diagram, and marking the points, the 
eccentrics may at any time be adjusted without difficulty. 



108 



HAND-BOOK OF LAND AND MARINE ENGINES. 



esaU 



Example. — Let F G and E C be the two straight lines 
right angles to each other ; the circle described with A B 
as a radius be the end view of the shaft; the circle de- 
scribed with A C as a radius be the circle described by the 
centre of the eccentrics ; and H I the line parallel to E 
C, and distant from it the amount of the lap and lead. 
Then, if F G represents the direction of the crank when 
on the centre, H and I will be the 
positions of the centres of the 
eccentrics, according to the rule. 
If, then, the points K and L, in 
which the lines A H and A I in- 
tersect the circle representing the 
shaft, be transferred to the shaft, 
by laying off on its end the two 
diameters, and the chords B K and 
L M, the eccentrics can readily 
be set. 

Whether the engine be vertical, 
horizontal, or inclined, the eccentric occupies the same 
position on the shaft. The wide part, or throw, and the 
crank are always at right angles to each other, excepting 
the departure from a right angle which the lap and lead 
make necessary, as shown by the lines C and E and H 
and I. To account for this position, it must be under- 
stood that the eccentric must commence to open the port 
before the crank reaches the centre, or, in other words, the 
eccentric must commence its stroke a little ahead of the 
crank. 

ECCENTRIC-RODS. 



Eccentpic-pods, like all other vibrating rods subjected 
to different strains, direct and angular, compression and 
tensile, or pull, are frequently of great length even in 




HAND-BOOK OF LAND AND MARINE ENGINES. 109 

engines of moderate size ; consequently, rigidity is required, 
in order that a steady motion may be transmitted from the 
eccentric to the valve. A long eccentric rod is desirable. 

Length of Eccentric-rod. — The length of the eccentric- 
rod is the distance between the centre of the crank-shaft 
and the centre of the rocker-pin, when the latter stands 
plumb. 

How to Adjust the Eccentric-rod. — Place the crank 
on the dead centre and the eccentric at 90^, or at right 
angles with the crank; then adjust the eccentric-straps 
and place the rocker in a perpendicular position. If 
the eccentric-catch adjusts itself to the rocker-pin without 
moving the latter in either direction, the eccentric is of' 
the proper length. 

Modes of attaching Eccentric - rods. — In some in- 
stances, the end of the eccentric-rod is turned tapering, to 
fit a corresponding hole in a sleeve cast on the forward 
strap of the eccentric, in which it is secured by a vertical 
key ; while in others, the rod is slipped loose into the sleeve 
and secured at both ends by jam-nuts: this arrangement 
affords the best facilities for adjusting the rod to its proper 
length. 

CRAMS. 

Cranks may be divided into two classes, single and 
double, — the former being most generally used for stationary 
engines, while the latter are more applicable to the engines 
of river-boats and sea-going steamers. Cranks are sub- 
jected to different strains, among which are most promi- 
nent, bending or deflecting, compression, and tensile. 
They should be considered as beams supported at one end 
and the load at the other ; consequently, the sectional area 
of the crank depends on the form and the length be- 
10 



110 HAND-BOOK OF LAND AND MARINE ENGINES. 

tween the centre of the crank-pin and the centre of the 
shaft. 

All single rotative engines are provided with heavy 
parts, such as fly-wheel, disk-cranks, and counter-weights, 
which also have a rotary motion when the piston is in 
action. These heavy parts acquire energy during the 
stroke to continue the motion past the centres, where the 
pressure on th^ piston produces no effective pressure on 
the crank-pin. 

The crank being the means most generally used for the 
convertion of reciprocating into rotary motion, the ques- 
^tion has frequently arisen, whether or not there is a loss of 
power connected with its use ; but upon examination, it 
will be found that the only loss of power incurred by the 
use of the crank is that absorbed by friction, w^hich is the 
coefficient of loss in the transfer of all forces. The idea 
of a loss of power in the crank arose from the common 
error of confoundiog power and pressure, and forgetting 
that a small force exerted over a great distance in a given 
time may develop as much .power as a large force exerted 
over a small distance in the same time. 

An examination of the connecting-rod of an engine in 
motion, will show that the two ends pass over different 
spaces in a given time. If, for instance, in one stroke, the 
end of the connecting-rod that is attached to the cross- 
head moves through one foot, the end which is attached to 
the crank-pin, and makes a half revolution in the same 
time, passes through 1*5708 feet. 

Suppose that an engine is placed with its crank on the 
centre, and steam is admitted ; no motion will be produced, 
and, consequently, there will be no power developed, and 
no expenditure of steam. But let the piston make a 
stroke ; the power exerted is equal to the force or pressure 
acting on the piston multiplied by the space passed 



I 

isedll 



HAND-BOOK OF LAND AND MARINE ENGINES. 



Ill 



through, or it will be 100 foot-pounds, assuming the data 
of the preceding instance. 

During the same time, the crank-pin has passed through 
a space of 1*5708 feet, and the force or pressure exerted 
has been 63*66 pounds, so that the power exerted during 
this time, or the product of 1*5708 multiplied by 63*66 
pounds, is 100 foot-pounds. Consequently, there is no loss 
of power in the use of the crank, all the power exerted on 
the piston being imparted to the crank. 

Examination of the Principles Involved in the Use of 
the Crank. — With a pair of compasses describe a circle; 
draw a line through the centre, from one point of the in- 




tersection of this line with the circle ; divide the latter into 
20 equal parts, 20 and 10 occurring at these points. Now 
suppose that the constant pressure of the steam in the cyl- 
inder be represented by 100, this pressure is communicated 



112 HAND-BOOK OF LAND AND MARINE ENGINES. 

to the crank by means of a connecting-rod, and we will 
suppose that the above circle is the circle described by the 
crank-pin, 10 and 20 coinciding, and with the division 10 
forming a right line with the centre of the crank-shaft and 
the centre of the cylinder; of course, the points 20 and 10 
are the two points where the pressure in the cylinder has 
no effect in turning the crank, called the " dead-points." 

The points 5 and 15 are the points at which the effect 
of the pressure on the piston is a maximum, decreasing 
each way to zero. Supposing, for simplicity, the direction 
of the connecting-rod to remain parallel with its first posi- 
tion, then the effect of any pressure communicated by it 
to the crank-pin is resolvable into two — one acting on the 
centre of the crank, and, of course, inoperative towards 
producing motion in it, and the other acting tangentially 
to turn the crank. 

The first of these is greatest at the commencement, or 
20 and 10 of the circle of the crank, and least at the points 
5 and 15 ; while the second is least at the first-named points 
and greatest at the last; and ^ this variation is (from the 
well-known principles of the composition and resolution 
of forces) in the ratio of the sines of the angle made 
between the direction of the crank and the direction of 
the connecting-rod. 

The subdivision of the crank-circle into 20 parts gives 
as the angle of each division 18°, and calling the radius 
of this circle 100, the sines of the respective angles formed 
by the crank and connecting-rods will represent the per- 
centage of power communicated by the latter to turn th( 
former. Thus : 



HAND-BOOK OF LAND AND MARINE ENGINES. 



113 



Grank-pin at 0°. 

" " 1 18^. 

" " 2 36^. 

" " 3 54''. 

" " ." 4 72''. 

" " 5 90°. 

" " 6 108°. 

" " 7 126°. 

" " 8 144°. 

'' " 9 162°. 

" " 10 180°. 



0.0 

.Sin 30.90 

" 58.78 

. " 80.90 

. " 95.11 

. " 100. 

. " 95.11 

. " 80.90 

. " 58.78 

. " 30.90 

. " 0.0 



Mean power, 63.11 

The pressure of the steam on the piston forces the 
connecting-rod twice the length of the diameter of the 
circle in the same time that the crank-pin travels through a 
space equal to the whole circumference of this circle; and 
as the circumference of this circle bears to twice its diameter 
the ratio of 100 to 63*6, it follows that the pressures on the 
crank and piston are inversely as the space through which 
they move. The effects of moving powers may be repre- 
sented, for comparison, by the product of the pressures into 
the spaces described in the same time. 

The power of the steam in the cylinder being 100, and 
moving through a space represented by 2, we may repre- 
sent it by 200 ; and the mean pressure on the crank, as 
shown above, being 63*11, moving through a space repre- 
sented by 3*1416, we may represent its effect by their prod- 
uct, 198*26, differing but 1*74 from the power given out 
,by the steam in the cylinder. This difference will appear 
smaller and smaller, according as we multiply the number 
of points in the circle, from which we calculate the mean 
pressure on the crank. 

The two foregoing formulas, introduced for the purpose 
10* H 



114 HAND-BOOK OF LAND AND MARINE ENGINES. 

of showing that the crank is no consumer of power beyond 
the friction incidental to the motion of all machinery, but 
gives out all the power it receives from the steam, are 
somewhat different in their conclusions, being made by dif- 
ferent calculi ; but they are both approximately correct. 

CRANK-SHAFTS. 

The cpank-shafl of an engine is the transmitter of the 
power developed and expended at its middle or extremi- 
ties, as the case may be. As the force exerted by the steam 
in the cylinder is thrown on the crank-pin, from thence to 
the crank, and in turn to the shaft, evidently, the strains 
imposed are not alike, — the pin is subjected to a shear- 
ing strain ; the crank, to a deflecting or bending strain ; 
and the shaft, to torsion and shearing strains. 

Crank-shafts may be made of either cast- or wrought-iron, 
and, when well proportioned, the former material answers 
very well, especially for large engines ; but when lightness 
and strength become an object, wrought-iron is the mate- 
rial generally used. 

PILLOW-BLOCKS, OR MAIN BEARINGS. 

The pillow-blocks, op main bearings, of a steam-engine 
rank next in importance to the cylinder and piston ; and as 
they are subjected to very unequal wear and strains, unless 
well proportioned and thoroughly fitted, they are liable to 
heat, and become a continued source of annoyance. Of 
course, by reducing the friction, the tendency to heat is also 
reduced. This can be done by making the revolving sur- 
faces smooth and using a good lubricant; but at very high 
pressures the lubricant is forced out from between the sur- 
faces ; the pjessure at which this occurs is supposed to be 
about 2000 pounds to the square inch of bearing surface. 



HAND-BOOK OF LAND AND MARINE ENGINES. 115 

FLY-WHEELS. 

The applications of fly-wheels are very general, as there 
are few stationary engines without them ; and it has also 
become quite common to communicate the power directly 
from the periphery of the fly-wheel, by using it as a pul- 
ley or drum, and transmitting the power through a belt or 
band. 

The fly-wheel is used as a regulator, or equalizer of mo- 
tion, wherever either the power communicated or the resist- 
ance to be overcome is variable. 

In the one case, the fly-wheel may be said to be a dis- 
tributer of power. The communicated impulses act on 
the mass in motion, and go to preserve the momenta, with- 
out disturbing very sensibly the regularity of movement. 
The effect of one impulse is so absorbed or distributed in 
the momentum of the wheel, that its efiect may be said to 
have hardly been diminished before the next impulse is 
received. 

In the other case, or where the fly-wheel is used to over- 
come a variable resistance, it may be considered a collector 
of power ; the power having been employed to get up the 
speed in the fly-wheel only, is retained in the mass in move- 
ment; and the whole of the power expended, with the ex- 
ception of that which has been lost through friction and 
resistance of the air, can be brought to bear at any instant 
upon the resistance to be overcome. 

When the crank and connecting-pod are in one straight 
line, as they must be twice in each revolution, the crank is 
said to be on its dead centre, because there the force of the 
piston is dead or ineffective. It is evident, that when the 
crank is at right angles to the connecting-rod, the latter 
has the mos't power on the former; but when the forward 
or backward dead centre is reached, there is no reason why 



116 HAND-BOOK OF LAND AND MARINE ENGINES. 

it should not remain there ; but the action of the fly-wheel 
then shows itself, for, having on it a certain accumulated 
velocity, it cannot stop, but goes forward, carrying with it 
the crank over the dead centres. 

Thus, through the momentum of the fly-wheel, no per- 
ceptible variation occurs in the velocity of the engine ; the 
unequal leverage of the connecting-rod is also corrected, 
and a steady and uniform motion produced. 

The fly-wheel, as before stated, is a regulator and reser- 
voir, and not a creator of motion. The accumulated ve- 
locity in the fly-wheel, where the motion is required to be 
excessively equable, should be about six times that of the 
engine when the crank is horizontal. 

As regularity of motion is of much greater importance 
in some cases than in others, the weight and diameter of the 
fly-wheel must depend on the work and the character of 
the machinery the engine is intended to drive ; so that in 
proportioning a fly-wheel to a given engine, attention must 
be paid to many particular circumstances rather than to 
any given rule. 

There are circumstances in which the use of a fly-wheel 
may be dispensed with : where a pair of engines work side 
by side, whose cranks are at difierent angles, so that one 
assists the other to pass the centres, or where smootlyiess 
of motion is not an absolute necessity. 

LINK-MOTION. 



Were it only requisite to provide a means of starting 
and stopping an engine, the mechanical appliance migh 
be very simple, but when reversing must be accomplislie< 
by the same gear, a very different mechanical arrange- 
ment becomes necessary. By means of the link the 
engineer is able at will to change the direction of the 



6 

I 



HAND-BOOK OF LAND AND MARINE ENGINES. 



117 



engine, with only the loss of time required for overcoming 
the momentum of the moving parts and developing the 
like in a reverse direction. 




A link operated by two fixed eccentrics forms, when 
properly suspended, an exact mechanical equivalent of 
the movable eccQutric. Unlike the latter, however, its 
motion is capable of an accurate adjustment, which prac- 
tically obviates the effect of irregularities in cut-off and 
exhaust closure, attributable to the angularity of the 
main connecting-rod. 

Horizontal motion, communicated to the link by the 
joint action of the eccentrics, is a minimum at the centre 
of its length, where it is equal to twice the linear advance, 
and it increases towards the extremities of the various 
periods of the block in the link, or of the link on the 
block, on the general principle that admission varies with 
the travel of the valve. 

The nature of the motion derived from the link is 
modified by the positions of the working centres, and 
most especially of the centres of suspension and connec- 
tion ; the centre of suspension is the most influential of 
all in regulating the admission, and its transition horizon- 
tally is much more efficacious than a vertical change of 
place to the same extent. 

As the vertical movement of the body of the link with 
the consequent slip between the link and the block is the 
least possible when the suspended centre lies in the centre 
line of the link, increasing as the centre is moved later- 



118 HAND-BOOK OF LAND AND MARINE ENGINES. 

ally, the centre line of the link is, in this respect, the 
most favorable locality for the suspension, though not 
always practicable for equal admissions. 

In practice it has been found that the stationary and 
shifting links have not the same neutral centres of sus- 
pension ; that, in general, the stationary link should be 
hung by a centre in the neighborhood of the middle of 
its length, and the shifting link towards one of the ex- 
tremities. 

The utmost period of expansion obtained by a station- 
ary link in mid-gear is 38 per cent, for 12 per cent, of 
admission, in which case the steam is cut off at less than 
one-eighth of the stroke, and expanded into a volume of 
50 per cent., or one-half stroke, — 4 times the initial vol- 
ume, exclusive of clearance, — after which it exhausts 
during the remaining half-stroke. 

With the stationary link the shortest admission is 11 
per cent., or one-ninth of the stroke, expanding into 50 
per cent., or 4J times the initial volume, Kefore the release 
takes place. 

With the shifting link, the smallest attainable admis- 
sion is about 17 per cent., or one-sixth of the stroke; this 
is about one-half more than what is obtained by the 
stationary link, the difference being due to the excess of 
lead yielded by the shifting. 

As the release takes place at half-stroke, the shifting 
link cannot expand the steam above three times its initial 
volume, exclusive of clearance. 

The average period of admission in full gear does not 
exceed 75 per cent., or three-fourths of the stroke. The 
admission may, however, be increased by forcing the 
mechanism of the valve beyond full gear — that is, by 
causing the block to work in the extreme overhung parts 
of the link, which must be extended for the purpose 






HAND-BOOK OF LAND AND MARINE ENGINES. 



119 



beyond the centres of connection ; by this expedient the 
throw of the valve is increased. 

The periods of expansion and release increase as those 
of admission are diminished. The motion of each eccen- 
tric prevails in that half of the link to which it is coupled, 
and at the centre the motion of the link is equally com- 
posed of the two eccentrics. 




:;S) 



The radius of the link is the length from C to the cen- 
tre of the eccentric, or the horizontal distance from the 
centre of the shaft to the centre of the link. 

Locomotives and screw-engines have on their main 
shaft two eccentrics and eccentric-rods for working the 
slide-valve. One of these eccentrics is for the forward or 
progressive, the other for the backward or retrogressive 
motion of the engine, and the same act which brings one 
into operation throws the other out. 

When the link is moved so as to bring the valve-stem 
pin into its centre position, that pin then becomes a pivot, 
without any rectilinear, reciprocating, or other motion 
whatever, being entirely at rest. When the valve-stem 
pin is thus in the centre of the link, the valve has no 
motion, but is at rest in the centre of the steam-chest 
covering all the three passages, which shuts out the ad- 
mission of steam to the cylinder. 

It follows that so long as the pin holds this central 



1£0 HAND-BOOK OF LAND AND MARINE ENGINES. 

position in the link, the engine cannot move by steam ; 
for, however it may be in the chest, it cannot reach the 
cylinder to act on the piston. Should it become necessary, 
for the purpose of adjusting any part of the machinery, 
to revolve the shaft by hand, it can be done with perfect 
safety, providing the link is maintained in a central 
position. 

The nearer the valve-stem pin is brought to either end 
of the link or either eccentric-pin, the greater will be the 
travel of the valve, and the more the steam- and exhaust- 
ports will be opened. 

When the forward eccentric-rod is brought nearest to 
the valve-stem, the engine under steam will move ahead ; 
when the backward eccentric-rod is brought nearest the 
valve-stem, the motion of the engine will be reversed. 

When an engine is standing under steam, the link 
should, in all cases, be placed at mid-gear, or, in other 
words, in a central position, so that the backward and 
forward eccentric-pins will be at equal distances from the 
valve-stem, — a necessary precaution to guard against 
accident. 

To start ahead, move the link until the forward eccen- 
tric-pin comes nearest to the valve-stem. 

To back, bring the backward eccentric-pin nearest to 
the valve-stem. 

To stop, bring the two eccentric-pins to equal distances 
from the valve-stem. 

To go ahead fast, move the link to full gear, or until 
the link-block is in the extremity of the link. 

To go slow, bring the centre of the link near the centre 
of the link-block. 

The following cut represents the form of link generally 
used on marine engines : the. link is raised and lowered 
by means of a screw, which receives its motion from a 



HAND-BOOK OF LAND AND MARINE ENGINES. 121 

pair of mitre-gears on the hand-wheel shaft ; the weight 
of the link, reach-rod, and sliding-block is counterbal- 



anced by the lever and balance-weight below the motion ; 
and thus it will be seen that the power required to shift 
the slide-valve is greatly- reduced. 

PROPORTIONS OP STEAM-ENaiNES ACCORDING TO 
THE BEST MODERN PRACTICE. 

Before any correct formula, by which to determine the 
proper proportions for steam-engines, can be deduced, there 
are many things to be considered ; permanent load, weight 
of moving material, nature of motion, etc. 

The load on the piston-rod consists of the piston at 
one end and the cross-head at the other ; consequently, the 
greater the length between these tAVO points, the more the 
rod is affected. For this reason, it is obvious that, when it 
becomes necessary to fix the area of the piston-rod, the 
pressure, area of cylinder, load, and length of travel must 
be duly considered. 

The connecting-rod being hung between a sliding and a 
11 



122 HAND-BOOK OF LAND AND MARINE ENGINES. 

rotary motion, the load is in some measure due to the 
length of the rod in proportion to the circle described. 
In the first case, the sliding point has a load on it due to 
the weight of the piston-rod beyond the stuffing-box, with 
the additional weight of the cross-head; in the second 
instance, the rotating surface is afiected by the weight of 
the rod and the weight of the crank. 

To determine the diameter of the crank-shaft, we must 
take into account the length of the crank as a lever, and 
the pressure of steam as the weight on the end of the same. 
The proportions of the crank-pin are likewise modified 
according to pressure, permanent load, length of stroke, 
shearing strain, etc. 

The thickness of a steam cylinder may be found by the 
following rule. — Divide the diameter of the cylinder plus 
2 by 16, and deduct a y^^ part of the diameter from the 
quotient, the remainder will be the proper thickness. 

The depth of the piston-rings should equal | the diam- 
eter of the cylinder. 

The thickness of the follower-plate should be the same 
as that of the cylinder. 

The whole thickness of the piston will therefore be | 
the diameter of the cylinder plus twice its thickness 
obtained by the rule above. 

The diameter of the piston-rod should be from i to | 
that of the cylinder for high-pressure engines, and 4 for 
condensing engines. 

The diameter of the crank-shaft may be about j% that 
of the cylinder if of wrought-iron, or y% if of cast-iron ; 
but it should be y^^ of wrought-iron if extra strength be 
required. 

The length of the crank-shaft bearing should be equal 
to li times its diameter, and in some cases it should be 
twice. 



HAND-BOOK OF LAND AND MARINE ENGINES. 123 

The diameter of the crank-pin should be from '2 to '25 
that of the cylinder. Its length should be from '275 to '35 
the diameter of the cylinder. 

The diameter of the wrist- or cross-head pin should be 
equal to that of the crank-pin, and its length the same. 

The diameter of the connecting-rod, in the neck, should 
equal that of the piston-rod, and should increase | inch 
in diameter, to the foot, from the neck to the middle. 

The diameter of the eccentric-rod in the neck should 
be 1^ times the diameter of the valve-rod, and should 
increase | inch in diameter to the foot of the eccentric. 

The diameter of the valve-rod should be from ^^ to ^^ 
that of the cylinder. 

The diameter of the boss of the crank, if cast-iron, 
should equal twice that of the shaft-journal. Its depth 
should equal the diameter of the shaft-journal multiplied 
by 7. 

The diameter of the crank at the pin should equal 
twice the diameter of the pin, and its depth at the pin 
should equal the diameter of the pin multiplied by 12. 

The thickness of the web of the crank should equal 
three times the diameter of the shaft-journal. 

The boss of the crank, if of wrought-iron, should equal 
the diameter of the shaft-journal or the pin multiplied 
by 4. 

The thickness of the crank should equal, the diameter 
of the shaft-journal multiplied by 6. 

The area of the crank at the centre should equal that 
of the shaft. 

The thickness of the straps should be equal to '44 of the 
diameter of the pins ; but for engines requiring great 
strength, they ought to be ^ the diameter of the pins. 

The breadth of the strap should equal 1*1 times the 
diameter of the pin plus j^^. 



124 HAND-BOOK OF LAND AND MARINE ENGINES. 

The distance from the slot to the end of the strap should 
equal '06 of the diameter of the pin. 

The breadth of the gib and key should equal 1*1 times 
the diameter of the pin ; the thickness should equal *3 
that diameter ; the clearance should equal ^ the diameter 
of the pin plus 2 divided by 16 ; the distance from the 
key-slot to the end of the block should equal '44, the 
diameter of the pin. 

The diameter of the steam-pipe should be the same as 
that of the crank-pin, or from '2 to '25 the diameter of the 
cylinder. 

The diameter of the exhaust-pipe should be from '25 to 
•3 the diameter of the cylinder. 

The length of the cross-head bearings should be equal 
to I the diameter of* the cylinder, and their breadth to ^^ 
of the same. 

The diameter and length of the rock-shaft bearing, if 
subjected to torsion strain, should be from \ to | the 
diameter of the engine-shaft ; if not subjected to torsion, 
\ the diameter of the engine-shaft will be sufficient. 

The diameter of the rock-shaft pin should not be less 
than that of the valve-stem ; and if an overhanging pin, it 
should be from 1\ to 1^ times the diameter of the valve- 
stem. 

In order to make the proportions more plain, it may be 
advisable to introduce an example; say, for instance, an 
engine with a cylinder 12 inches in diameter and 30 inches 
stroke. Thickness of cylinder, '| inch ; depth of piston- 
ring, 3 inches; diameter of piston-rod, \\\ inches; diam- 
eter of crank-shaft, if wrought-iron, 4*8 to 5 inches, if cast- 
iron, 8 to 8^ inches ; length of bearing, 7| inches ; diam- 
eter of crank-pin, 2*4 to 3 inches ; length of crank-pin, 3'3 
to 4 inches; diameter of connecting-rod in the neck, Ijg 
inches ; diameter of eccentric-rod, 1\ inches ; diameter of 



HAND-BOOK OF LAND AND MAHINE ENGINES. 



125 



valve-rod, 1 inch ; diameter of wrist-pin, 2*4 to 3 inches ; 
length of wrist-pin from 3-3 to 4 inches; thickness of 
stub-straps, 1| inches ; breadth of straps, 3| inches ; distance 
from slot to end, 1-8; breadth of gib and key, 3| inches; 
thickness of gib and key, | inch ; clearance, 2 inches to 
•218 inch ; from key-slot to end of block, 1| inches ; area 
of steam-port, 7i inches ; length of port, 7*2 inches ; width, 
1 inch ; width of exhaust-port, 1^ inches ; diameter of 
steam-pipe, 3 inches ; diameter of exhaust-pipe, 3| inches. 




c F 

Section of a Corliss cylinder showing the piston-valves, steam- and 
exhaust - chests. A, B, Steam-valves; C, D, Exhaust - valves ; E, 
Steam-pipe ; F, Exhaust-pipe. 





11* 



Corliss Valves. 



126 HAND-BOOK OF LAKD AND MARINE ^NGINES. 




KAND-BOOK OF LAND AND MARINE ENGINES. 127 

SETTING UP ENGINES. 

For setting up engines, like setting valves and putting 
engines in line, no special instructions can be given, as 
the circumstances of design, construction, location, etc., 
vary so much ; and also the fact that it is rare to find 
two men agreeing on the best way of performing this kind 
of work ; almost every engineer having his own peculiar 
way of doing it ; yet it may be possible to give general 
instructions on this point. 

Having decided on the location where the engine is in- 
tended to stand, line down from the side of the main shaft, 
if there be any, to the floor at three or four different places 
in its length. If there be no shafting, measure from the 
side of the building to the centre, at five or six points in 
its length ; then strike a line across all these points. This 
line will show with sufficient accuracy the line of the main 
shaft, or the line of the building, as the case may be. From 
this line then measure to the point at which the excava- 
tion is to be made ; and after the earth is removed to a 
sufficient depth, set up a wooden tamplet on four props, in 
which to hang the foundation bolts, this tamplet being an 
exact counterpart of the bottom or under side of the bed- 
plate. 

Now drop a plumb-line from two points on the line of 
the main shaft or the centre line of the building, and from 
this plumb-line measure to the tamplet, in order to ascer- 
tain if the latter is square with the line of the building or 
the shaft, as the case may be. Then, after the foundation is 
raised to the proper height, and the bed-plate placed in its 
position and levelled, draw a line through the centre of 
the cylinder, and intersect this line with another passing 
through the centre of the main pillow-block on the bed- 
plate. This latter line will give the exact location of the 



128 HAND-BOOK OF LAND AND MARINE ENGINES. 

off pillow-block, as the axis of the shaft must be at right 
angles to the horizontal line passing through the centre 
of the cylinder, and also at right angles to a vertical line. 
The fly-wheel may now be swung between the pillow- 
blocks with a block and tackle, and the shaft slipped 
through it ; the caps of the pillow-blocks screwed down, 
the piston, cross-head, connecting-rod, eccentric- and valve- 
rods adjusted, and all the minor details finished up. 

DEAD CENTRE. 

A difficulty is often experienced in finding what is 
called the " dead centre," or the position of the crank cor- 
responding to the end of the stroke ; although the experi- 
enced engineer can in a majority of cases tell by his eye, 
yet in others, in consequence of peculiarity of design and 
complication of parts, he finds it very difficult. 

A very accurate way of finding the dead centre in hori- 
zontal engines, is to place a spirit-level on the top or bottom 
of the strap of the connecting-rod, and move the crank up 
or down until the centre is found. Or, if this should be 
found inconvenient or impracticable, a circle may be de- 
scribed with a pair of dividers on the centre of the crank- 
shaft equal in diameter to the shoulder of the crank-pin ; 
then place the spirit-level parallel with the shoulder of the 
crank-pin and the outer edge of the circle ; then by moving 
the crank up or down, as the case may require, the centre 
can be accurately found. The centres of vertical and 
beam engines can be found by means of a plumb-line. 

HOW TO PUT AN ENGINE IN LINE. 

An engine is in line when the axis of the cylinder 
and the axis of the piston-rod in all positions are in one 
and the same straight line. This line extended should 



HAND-BOOK OF LAND AND MARINE ENGINES. 129 

intersect the axis of the engine-shaft, and be at right angles 
to it. The guides should also be parallel thereto. The 
axis of the shaft must be level, but the centre line of the 
cylinder may be level, inclined, or vertical, according to 
the kind of engine. 

Take oif the cylinder-heads and remove the piston-rod, 
cross-head, and connecting-rod; then extend a fine line, as 
nearly as may be by the ordinary means of measurement, 
through the centre of the cylinder, and let it pass beyond 
the crank-pin when at outer centre ; also let it extend out- 
side the rear end of the cylinder and firmly secure each 
end to some fixed object at these extreme points. Stretch 
this line as tightly as it will bear without breaking, and 
then begin to g^t it in exact central position by rod meas- 
urements. 

Mark four points with a centre-punch at equal distances 
from each other around the bore of the cylinder, say, top 
and bottom and on each side at each end, and then, by a 
trial with a small pointed piece of hard wood, set the line 
so that when one end of the wire rests on each of the four 
points successively, the other end will just feel the line ; 
next see where this line passes the centre of the shaft. If 
they coincide, then the cylinder is in line with the shaft ; 
if not, they must be put in line with each other. It is often 
difl[icult to move cylinders and shafts, and as one or the 
other must be remoyed, in some cases both, in this event 
only skill and judgment can decide which to do and how 
to do it. 

No special directions can be given how to move the 
cylinder and shaft into line with each other, because they 
are so diflferently constructed ; but trusting to the skill of 
the engineer to secure these two points, the next thing to 
do is to set the shaft at right angles to the line, and to make 
it level, also. To do these, turn the shaft until the crank- 

I 



130 HAND-BOOK OF LAND AND MARINE ENGINES. 

pin almost touches the line ; and then find, by' a rod or in- 
side calipers, if the line lies evenly between the two collars 
of the pin; if not, note the distance from either one, and 
then turn the shaft until the pin almost touches the line 
on the other side, and apply the measure to corresponding 
places on the collars of the pin. The difference in the 
measure, if any, will show which way the end of the shaft 
must be moved to make these measures equal. 

The exchanging of the crank-pin from side to side may 
have to be repeated several times and remeasured, and the 
shaft moved, before these measures can be made equal. 
The shaft may require moving endwise in order to get the 
line to lie evenly between the two collars ; but when the 
turning of the shaft half around brings both collars of the 
pin the same distance from the line, the shaft is then at 
right angles to the centre line of the cylinder. 

In order to level the shaft by the same method, drop a 
plumb-line, passing by the centre of the shaft and by the 
centre line of the cylinder, also ; then by turning the pin up 
and down to the near touching-points of the plumb-line, and 
raising or lowering the outer end of the shaft until the col- 
lar on the pin is the same distance from the plumb-line in 
both positions, the shaft may be said to be level, or, which 
is the same thing, it is made at right angles to a plumb-line. 

It remains now* to bring the guides into line with the 
cylinder, and this may be done by. direct measurement 
from each end of each guide (if there are two) to the line, 
moving them until they are parallel to the line and to one 
another. A spirit-level may be placed on their top faces 
to show how to adjust them to the horizontal ; if no level is 
at hand, then a true square and plumb-line may be used ; 
and if not, straight-edges placed across the guides, and 
measurements made down to the centre line, will determine 
the line of them. 



HAND-BOOK OF LAND AND MARINE ENGINES. 131 

HOW TO REVERSE AN ENGINE. 

An engine may have its motion reversed for a short 
time, and for slow speed, by the use of the starting-bar ; 
but for continual running, and particularly for high speed 
in the absence of the link, the eccentric must be turned 
on the engine-shaft around to the position required by the 
reversed motion. 

With a small chisel or centre-punch make a mark on 
the engine-shaft, and make a corresponding mark on the 
side of the eccentric at the same point. Place one point 
of an outside calipers in the mark on the shaft, and with 
the other point find the centre of the shaft ; here also 
make a mark. Now move the eccentric round on the shaft 
in the direction in which the engine is desired to run, until 
the mark on the hub of the eccentric is brought parallel 
with the last mark made on the shaft; then make the eccen- 
tric fast, and the engine will move in the opposite direc- 
tion from that which it did before the eccentric was moved. 

SETTING VALVES. 

It may seem strange that any person claiming to be an 
engineer should be found unable to properly set the valves 
of a steam-engine; and yet it is a fact, that there are 
thousands of persons having charge of engines, who are 
unfit, by want of practical Jinowledge, to do so correctly. 

This may arise from the fact that in none of the works 
heretofore written on the steam-engine, does there appear 
to be any accurate method laid down for the proper setting 
of valves ; an omission which it is difiicult to account for, 
as it must be admitted that the setting of the valves of 
steam-engines is among the most important duties the 
engineer has to perform, involving, as it does, nicety of 
calculation and mechanical accuracy. 



132 



HAND-BOOK OF LAND AND MARINE ENGINES. 



bed!| 



A slide-valve may be properly designed and constructed 
and yet be unable to perform any of its proper functions, 
in consequence of being improperly set, as the steam may 
be admitted too soon or too late, and the exhaust fail to 
open and close at the right time, in consequence of which 
the useful effect of the steam is lost and the power of the 
engine diminished. 

HOW TO SET A SLIDE-VALVE. 

Place the crank at 180^, or dead centre, and the eccentric 
at 90"^, or at right angles with the crank ; now adjust the 
eccentric-rod so that the rocker will stand in a perpen- 
dicular position ; next place the valve centrally over the 
ports as shown in Fig. 1, and get it equally divided on the 

90^ 





Fig. 1. • 
rod, so that with the motion of the engine, when all is con- 
nected, the valve will travel equally to either extremes 
from its central position. Then turn the eccentric forward 
on the shaft, in the direction in which the engine is intended 
to run, until the valve shows ttie steam-port just beginning 
to open, as in Fig. 2. If more lead be required, move the 





Fig. 2. 



HAND-BOOK OF LAND AND MARINE ENGINES. 133 

eccentric farther ahead, until the valve opens the port to 
the amount of lead required. If lap be necessary, move 
the eccentric back the required distance, when it will be 
found that, if the valve and ports have been laid out ac- 
cording to the proportions given under the head of slide- 
valves, the engine will work well. 

All valves of steam-engines, whether slide, conical, or 
vibratory, are set in precisely the same way, as the crank 
must occupy the same positions when the steam and ex- 
haust-valves commence to open, regardless of the design 
or construction of the engine or valves. 

To set poppet or conical valves, it is only necessary to 
place the crank on the dead centre, and move the cams on 
the cam-bar until the steam and exhaust-valves have the 
necessary amount of lead — the throw of the cams to give 
the required lift of the valves being previously deter- 
mined, the movements of the cam-bar, the lifts of the 
valves, the speed, etc., being influenced by the action of 
the governor in stationary engines. But it must be under- 
stood that every different valve requires different setting ; 
a change of speed will necessitate a change in the position 
of the valve ; if the throw of the valve be altered, its lead 
must also be altered. 

One of the best helps to correct valve-setting is a good 
indicator, as there is nothing known which shows the ac- 
tion of the steam in the cylinder so correctly as this in- 
strument. It tells exactly where the steam goes in and out 
of a cylinder, because it maps down the motions of the 
steam as determined by the motions of the valve and pis- 
ton, recording faithfully the times and the pressures as 
they actually are, which may be very different from pre- 
sumed times and pressures as shown by the mechanical 
movements of the valve and gear. 
12 



134 HAND-BOOK OF LAND AND MARINE ENGINES. 




SETTING OUT PISTON PACKING. 

Among the most important duties an engineer has to 
perform, is that of the setting out of piston packing, and 
as, like many other details of the steam-engine, no general 
instructions can be given for its adjustment, therefore a 
good deal depends on the capability and intelligence of 
the engineer. 

The first thing to be done, in order to properly adjust 
the packing, is to see that the piston is exactly in^ the 
centre of the cylinder. This can be ascertained by measur- 
ing, with a pair of inside calipers, from the centre of the 
piston to the inside of the cylinder at four different points. 
To insure accuracy, calipers with a long and a short leg 
are generally used, the short leg being inserted in the 
centre of the piston-head and the circle of the cylinder 
inscribed with the long one, which will show precisely the 
position of the piston in the cylinder. The rings should 
then be set out sufficiently tight to form a steam-tight 
joint with the inside of the cylinder, and no more. If the 
cylinder is true and in good condition, the springs of the 
proper tension, and the rings well proportioned and fitted, 
there is no reason Avhy the piston should leak. 



HAND-BOOK OF LAND AND MARINE ENGINES. 135 

Whether the piston is leaky or not can be ascertained 
by removing the back-head of the cylinder and admitting 
steam to the other end. To make such a trial, the crank 
should be placed at half-stroke, as many pistons perfectly 
steam-tight at either end would leak when at half-stroke, 
in consequence of the cylinder being worn larger in the 
middle than at the ends. 

Brass or composition rings should be adjusted while 
the cylinder is warm, as, if set out when cold, in conse- 
quence of their great limit of expansion when heated, they 
become too tight, and generate a great amount of friction. 

In many instances, where engines fail to develop the 
necessary amount of power, it is attributed to the leaky 
condition of the piston, and, as a remedy, the rings are 
set out to such an extent that, instead of the power of the 
engine being increased, it is materially diminished, thus 
aggravating the evil that was sought to be removed. 




PISTON- AND VALE-ROD PACKING. 

There is probably no part of the steam-engine more 
frequently out of order, or gives greater annoyance to the 
engineer, than the piston- and valve-rod packing. Con- 
sequently, there is at present, as there always has been 
since the advent of the steam-engine, a great need of a 
permanent and reliable piston-rod packing. Such an 
article could not fail to amply remunerate the inventor. 



136 HAND-BOOK OF LAND AND MARINE ENGINES. 

as it would not only lessen the labor of the engineer, but 
be productive of very economical results to the owners of 
steam-engines. 

A vast deal of study and ingenuity have been devoted 
to the removal of this annoyance, and the production of a 
durable packing, but so far without any very satisfactory 
results. Wire gauze, gum, soapstone, jute, asbestos, and 
a great variety of other materials, have been tried, but 
have failed to meet the requirements of a permanent piston- 
rod packing. 

In the early days of the steam-engine, hemp was the 
material most generally used, and answered very well, aS 
it had the advantage of being always ready for use, and 
requiring no special tools, particular size of stuffing-box, 
or extra skill to use it; but its usefulness had a very 
narrow limit, particularly where steam of a high pressure 
was used, as it soon lost its elasticity, and consequently 
became worthless. 

Soapstone gives tolerably good satisfaction, as, when 
first put in, it has the advantage of producing less friction 
than any other material used for the purpose ; but it has 
the disadvantage of becoming hard, which is very objec- 
tionable ; as, when packing loses its spring or elasticity, 
it greatly interferes with the smooth and easy working of 
the engine, particularly in the case of those out of line. 

The failure of any of the different kinds of packing 
now in use to give satisfaction might be attributed in part 
to a want of depth in the stuffing-boxes of modern built 
engines, as, when only a small quantity can be used at a 
time, the stuffing-boxes have, of necessity, to be screwed 
up very tight, which has the effect of producing extra fric- 
tion, which soon renders it worthless. 

Engines in general are packed less frequently than they 
should be ; but this is a mistake, as all that is saved 






A 



HAND-BOOK OF LAND AND MAHiNE ENGINES. 137 

packing is frequently lost by the fluting of the rods, when 
the packing becomes hard and dry. 

It is always better to have packing suflSciently large to 
admit of flattening before being inserted in the boxes. 

Before packing the piston- op valve-pods, all the old 
packing should be removed, also all dust or dirt that may 
have accumulated in the stufiing-boxes. The rings should 
be inserted in opposite directions, so as to break joints; but 
the ends of the rings should not be permitted to meet, as 
this has the efiect of preventing them from hugging the 
rod when they stretch. After the packing has been 
screwed down into the bottom of the box, the nut or nuts 
should be unscrewed one or two threads, in order to allow 
it to expand. 

Old filas or other rough instruments should never be 
used for removing packing from the boxes, as they have a 
tendency to scratch the rods ; but every engineer should 
provide himself with a smooth steel packing -bar and 
packing-hook to use for that purpose. 

If, after an engine is packed, the leakage should con- 
tinue excessively around the rods, it is always better to 
remove one or two pieces of the packing, and replace them 
again, than to continue screwing up the stufling-box. 
When it becomes necessary to tighten up the packing, it 
will be found of great advantage to do so when the engine 
is standing still. 

Piston- and valve-rod packing should always be kept 
in a clean place, and out of the reach of dust, sand, ashes, 
or any substance that would be likely to cut or flute the 
rods. 

The proper size of packing for any rod is one-half the 
difference between the diameter of the stufiing-box and 
the diameter of the rod. 

If a stuffing-box is extra large, and the quantity of 
12^ 



138 HAND-BOOK OF LAND AND MARINE ENGINES. 

packing on hand be insufficient, one ring of clean lead 
pipe inserted in the bottom of the box answers a very 
good purpose. ^ 

CUT-OFFS. 

Cut-off engines are engines having their steam-valves 
so controlled by the governor as to promptly cut ofl* the 
steam at any point from zero to half-stroke ; the cut-off 
taking place earlier or later to accommodate the varied 
loads on the engine and varied pressures in the boiler, — 
the object being tp obtain full boiler pressure at the com- 
mencement of each stroke, and maintain it to the point of 
cut-off, leaving the balance of the stroke to be completed 
by expansion, — the speed of the engine being controlled 
by the cut-off, and not by throttling. 

Until quite recently, the common method of regulating 
the flow of steam from the boiler to the cylinder has been 
by the throttle- valve — a kind of "damper" — in the 
steam-pipe, which is turned as the speed increases, and 
chokes off the supply. An engine controlled in this way is 
in a condition somewhat like that of a horse restrained 
by a brake applied to the wheels, and compelled to exert 
more strength than is necessary. This relic of barbarism 
is fast giving place to the system referred to in the fore- 
going paragraph, which removes the brakes from the 
wheels and puts the bit in the horse's mouth instead. 

In the old throttling system the fury of the imprisoned 
vapor was expended in a violent struggle to pass through 
a narrow opening, which at best allowed only a fraction 
of its power to be expended in driving the engine ; in the 
new cut-off system a large or small quantity of the steam, 
according to the requirements of the work, is allowed at 
each stroke to act with all its vigor against the piston. 

The economy of a high-pressure steam-engine is exactly 



HAND-BOOK OF LAND AND MARINE ENGINES. 139 

in proportion as its average piston pressure is higher than 
its pressure when it exhausts, provided the pressure shall 
not fall below that of the atmosphere; the highest economy 
being attained when the stroke is commenced with full 
boiler pressure, and the^steam quickly and completely cut 
off at a point in the stroke that allows the pressure to fall 
to or very near that of the atmosphere ; the full boiler 
pressure to be maintained from commencement of stroke 
to point of cut-off. The exhaust capacity must also be 
ample to prevent back pressure. 

GOVERNORS. 

The US3 of the governor is to preserve a perfectly 
regular speed in the engine, by varying the supply of 
steam as the work of the engine varies, which is an object 
of paramount importance in the prosecution of many 
manufacturing purposes, particularly in cases where, in 
consequence of the peculiar character of the work, it is 
found impossible to confine the variation in power within 
narrow limits. 

Centrifugal force has received the most attention, and 
nearly all governors since the days of Watt have been 
constructed on that principle ; consequently, hundreds of 
patents have been issued to inventors in which it has 
been attempted to combine sensitiveness of action and 
strength ; but the problem still remains unsolved, as all 
ball governors have the defects of requiring heavy balls, 
and of demanding a wide range of action where they have 
considerable force to overcome. 

It is well known that a governor that is very sensitive 
cannot be very powerful, nor can one that is very power- 
ful be very sensitive ; and that, in order to obtain great 
power from the ordinary ball governor, it is necessary to 



140 HAXD-BOOK OF LAND AND MARINE ENGINES. 

use very heavy balls or springs, or a very high speed, on 
the principle that a great resistance requires a great con- 
trolling force. 




The Huntoon Governor, 

The annexed cut represents the Huntoon Governor, in 
which it will be noticed that the fly-balls are dispensed 
with, and the principle of the screw-propeller adopted, 
and which is claimed to be the only isochronous * governor 
in this country. 

In this governor, a screw, rapidly rotating in a closed 
tank containing oil or water, exerts a force in the line of 
its axis, which is made use of in operating the throttle- 
valve. While the engine is at speed, no movement of the 
valve occurs, but should the speed diminish, a weighted 
arm forces back the screw and the valve opens. It will 
continue to open until the engine comes up to the proper 

*" Uniform in action and time. 



HAKD-BOOK OF LAND AND MARINE ENGINES. 



141 



speed again, whatever the conditions as to the load or 
steam pressure. 

Should the speed exceed that intended, the screw acts 
more energetically upon the liquid in which it works, and 
the increased effort is sufficient to overcome the resistance 
of the weighted arm, and to close the valve until the 
proper speed is again acquired. 

All marine engines, but especially screw engines, are 
liable to sudden fluctuations of speed from the varying 
immersion of the propeller in a rough sea ; and the neces- 
sity of employing some species of governor to redress 
these irregularities has long been perceived. 




Interior View of the Working Parts of the Huntoon Governor. 

The common form of governor that is used on land 
engines is obviously inapplicable to such a purpose, as 
the balls would open and close by the heaving of the 



142 HAXD-BOOK OF LAND AND MARINE ENGINES. 

ship. Various kinds of marine governors have been pro- 
posed to supply the want for which this governor has 
proved itself peculiarly adapted, as it has been applied 
to marine engines, and been found to answer all the re- 
quirements of a first-class marine governor. 

Governop- spindles working through stuffing-boxes 
should be frequently and carefully packed, as, when the 
packing becomes old and dry, if screwed up to prevent 
leakage, it interferes with the free action of the governor. 

Governors should always be kept perfectly clean and 
free from accumulations induced by the use of inferior 
oil, as such gummy substances have a tendency to inter- 
fere with the easy movement of the different parts. 
Many first-class regulators have been condemned as not 
being capable of controlling the engine at a uniform speed, 
when all that was required to restore them to their original 
accuracy was simply a good cleaning. 

THE ALLEN GOVERNOR. 

The cut on the opposite page represents the Allen 
Governor, the peculiar action of which allows the use of 
a valve of large area, thereby admitting to the engine- 
cylinder the greatest possible boiler pressure at each stroke 
of the piston. Within a corrugated cylinder, which has 
small projecting ribs on its interior periphery, and which 
is partially filled with oil, a paddle-wheel is caused to re- 
volve by a spindle passing through one end of the cylinder, 
driven by a belt communicating with the fly-wheel shaft. 
The tendency of the revolving paddle-wheel is to cause 
the cylinder to move in the same direction. 

On the opposite side to the revolving spindle is a trun- 
nion, or short spindle, fixed to the cylinder, attached to 
which is a wheel carrying a set of movable weights sus- 
pended by a chain, the speed of the engine being regulated 



HAND-BOOK OF LAND AND MARINE ENGINES. 



143 



by the number of weights. Attached to the wheel and 
keyed on the end of the short spindle, is a pinion revolving 
with the cylinder, and working in a toothed sector ; the 
arm of which, being fixed on the spindle of the throttle- 
valve, opens or closes it as the oil cylinder moves with the 
paddle, according to the variation of load thrown on the 
engine. When used with variable cut-ofi* engine, the arm 
is attached direct to the cut-off. 




The Allen Governor. 



It will be seen that the weights are raised and lowered 
in a nearly vertical line, and, unlike those of other gov- 
ernors, remain the same at every point of their suspension. 
The high rate of speed used acts advantageously in making 
the governor very sensitive ; and all parts being lubricated, 



144 HAND-BOOK OF LAND AND MARINE ENGINES. 



I 



it works with the smallest amount of friction. The cen- 
trifugal or ball principle being entirely abandoned, the 
movable weights are suspended as easily at one point as 
another, by the action of the paddle-wheel in the oil 
cylinder ; and from this fact, together with others peculiar 
to its construction, it is said to be capable of effecting a 
great saving in fuel, besides considerably increasing the 
power of the engine. 

The valve is constructed with a double disk in a tubular 
form, and is perfectly balanced, there being no spindle, as 
in the ordinary throttle-valve, to interfere with its equilib- 
rium. The valve is moved by means of a lever, and is 
opened and closed by a rocking motion of a steel spindle, 
which is covered with brass, insuring the greatest possible 
durability. 

The great secret of the success of this governor seems 
to be that, while it is very sensitive and requires but little 
power to run it, upon the least variation from the required 
speed, it can instantly eiert upon the valve or cut-oif to 
which it is attached all necessary force, up to a thousand 
pounds if required — a quality not possessed by ball gov- 
ernors. These governors have been applied to all kinds of 
land and marine engines, and are said to have given entire 
satisfaction. 

Rules for Calculating the Size of Pulleys for Gov- 
ernors. — To find the Diameter of Governor Shaft-pulley, — 
Multiply the number of revolutions of the engine by the 
diameter of the engine shaft-pulley, and divide the product 
by the number of revolutions of the governor. 

To find the Diameter of the Engine Shaft-pulley, — Mul- 
tiply the number of revolutions of the governor by the 
diameter of the governor shaft-pulley, and divide the prod- 
uct by the number of revolutions of the engine. 



HAND-BOOK OF LAND AND MARINE ENGINES. 145 

THE CATARACT. 

The cataract supplies the place of the governor in the 
single-acting Cornish pumping-engines. It consists of a 
small pump-plunger and valve, set up in a cistern of cold 
water, the valve opening inwards, so that when the plunger 
ascends, the water passes through, it being supplied by a 
cock, which is worked by means of a rod from the beam 
overhead. If the cock be shut, the plunger cannot de- 
scend ; but if slightly opened, it will descend gradually ; 
and as soon as a certain quantity of water has passed 
through, its weight opens the injection- valve and conden- 
sation takes place, when the engine can complete its stroke ; 
for the engine can only make the stroke as the water is 
supplied for condensation. 

In this manner, the cataract regulates the speed of the 
engine ; for if the cock be fully open, condensation takes 
place at once, and if only partly open, condensation will 
be delayed until the water is supplied. 

There are other varieties of cataract employed besides 
that here described, but they all depend upon the same 
general principle. In some cases air is used instead of 
water, and in others a cylinder of oil is employed, fitted 
with a piston with a valve, after the manner of a pump- 
bucket and a small side-pipe, fitted with a cock, which 
communicates between the spaces on each side of the piston. 

When the piston of this cataract is forced down, the oil 
easily ascends through the valve into the upper part of 
the cylinder ; but when it is drawn up, the oil can only 
escape by the curved pipe, from the space above the piston 
to the space beneath it, by passing through the contracted 
orifice of the cock ; and, though a considerable counter- 
balance be applied, the piston, if the cock be partially 
closed, can ascend but slowly. The effect is the same as 
in the arrangement first described. 
13 K 



146 HAND-BOOK OF LAND AND MARINE ENGINES. 



J 



WRIGHT'S HIGH-PRESSURE ENGINE/ 

This engine is built upon a solid, square, cast-iron bed- 
plate. The cylinder is fitted with Wright's patent slide- 
valve cut-off, worked by steel cams upon a horizontal 
shaft, to which a longitudinal movement is given by the 
governor. 

The cylinder is connected to the main pillow-block 
bearing by a strong wrought -iron brace rod. About 
the centre of this rod is located a cast-iron standard to 
steady the rod, and also to furnish a bearing for the rock- 
shaft. The governor, it will be noticed, is enclosed in a 
brass shell or urn, and is located upon the top of this 
standard, and is driven by a belt from the crank-shaft. , 
The governor-spindle passes down through this standard, 
and gives a longitudinal movement to the cut-off shaft 
through levers which vary the cut-off to any point in the 
stroke necessary to balance the load on the engine. 

The cut-off cams upon the side shaft have a rocking mo- 
tion, derived from an eccentric on the main shaft com- 
municating with a bell-crank, and from this bell-crank 
through a universal connection with the side shaft. 
This one eccentric gives the motion not only to the cut- 
off, but to the exhaust- valves. The concentrating of nearly 
all the valve-gearing in one place adds not only to the 
beauty and simplicity of the machine, but is much more 
convenient to adjust and handle. 

An unhooking arrangement is fitted to the pin in the 
belt-crank, whereby the engine can be stopped and reversed 
by hand at pleasure. 

The cross-hesd is carried in cast-iron slides, which are 
solid and cast on the bed. The feature of the cross-head 
is its stability, which is secured by its having a very broad 
* See page 20, 



HAND-BOOK OF LAND AND MARINE ENGINES. 147 

bearing on the bottom and sides, as also a top bearing with 
brass gibs. These engines have acquired a very wide 
reputation on account of their excellent performances. 

HAWKINS AND DODGE'S HIGH-PRESSURE ENGINE.* 

The bed-plate of this engine is cast in one piece, of a 
depth and form to give it the necessary rigidity. The 
cylinder has cast on one side a shelf for the valve-seat, with 
steam -.ports cored therein, on which the steam -chest, con- 
taining the main and cut-off valves, is bolted. 

By taking the nuts off the bolts, the cover, chest, and 
valves may be easily removed, thus making the valve-seat 
easy of access, if, from wear or other causes, the valves 
may need refitting; which, on engines with the steam- 
chest cast on the side of the cylinder, is often a difficult 
and unsatisfactory undertaking. 

The main valve is an ordinary slide-valve, operated by 
an eccentric ; it is formed with four narrow ports on its 
back corresponding to the same arrangement of ports in 
the cut-off valves, which work on the planed surface of its 
back, they being operated entirely by a Porter governor. 
By the simple adjustment of the lever on the governor- 
rod, they may be made to cut-off at any point of the 
stroke, while the periods of steam inlet and exhaust are 
unaffected. 

The rods are of steel, and all connections straight ; 
the bearings are large and long, rendering them less 
liable to cut and wear ; the different parts, besides being 
bolted, have taper dowel-pins fitted into reamed holes, so 
that the whole may be taken apart and put together again 
in perfect line. 

The engine consists of but few parts ; it is constructed in 

* See page 24. 



148 HAND-BOOK OF LAND AND MARINE ENGINES. 

a compact and symmetrical form, and finished in the best 
style of workmanship ; and is liable to no derangement, and 
requires but ordinary care to keep it in working order. 
The cylinder is encased in a neat, polished sheet-brass 
cover or fluted cast-iron jacket, thus preventing radiation. 
The reputation of these engines for economy and dura- 
bility stands deservedly high. 

WATTS AND CAMPBELKS HIGH-PRESSURE ENGINE.* 

The most remarkable features of this engine are the 
valves and valve-gear. There are four valves, two steam 
and two exhaust, which are operated by cams, the throw 
of which is controlled by the governor. The expansion- 
gear is Hornig's cut-off, which opens and closes the valves 
suddenly, and retains them at rest at full port, opening 
while the steam is passing in or out. 

In consequence of the perfect arrangement of the valve- 
gear, the steam is admitted and exhausted very freely, 
which has the effect of preventing the possibility of much 
back pressure. 

The bed-plate is heavy and well proportioned; the 
cylinder is protected by a metallic jacket, and the whole 
engine presents a very neat and substantial appearance. 

THE BUCKEYE HIGH-PRESSURE ENGINE. 

The cuts on pages 52, 53, represent the Buckeye au- 
tomatic cut-off engine, which is claimed to satisfy all the 
conditions necessary for the highest attainable economy 
in the use of steam-power. The steam is admitted to the 
cylinder through the slide-valve (a cut of which is shown 
on the opposite page) instead of around it. It enters the 
valve through circular openings in its back, and is 

'^^ See page 37. 



haintd-book of land and marine engines. 



149 



admitted from thence to the cylinder through two ports, 
which are alternately brought to coincide with the cylin- 
der-ports. 

To the openings in the back of the valve are fitted 
steam metal self-packing rings, which serve the purpose 
of insuring a steam-tight connection between the interior 
of the valve and the live-steam chamber in the back of 
the chest. The area of these openings is made just suffi- 
cient to hold the valve to its seat; hence it is as nearly 
balanced as is practicable or desirable. As the valve- 
chest contains only exhaust steam, the engines may be 
run with the chest-lid removed, and any leakage readily 
detected. 




The exhaust takes place kt the ends of the valve into 
the ends of the chest, thence through ample passages into 
the exhaust-pipe, passing downwards, as shown in cut on 
page 52, thus avoiding the tortuous exhaust passage in- 
volved in the use of the common slide-valve. 

The cut-off valve works inside of the main valve, and 
alternately closes the ports leading to the cylinder. The 
fixed eccentric operates the main valve, and an adjustable 
13* 



150 HAND-BOOK OF LAND AND MARINE ENGINES. 

one operates the cut-off valve through the medium of a 
small rock-shaft, which works in a bearing in the rock- 
arm of the main-valve gear, and moves with it. The 
movement of the cut-off valve, relatively to its seat in the 
main valve, is thus, both as to time and extent, just what 
its eccentric would produce if the valve worked in a sta- 
tionary seat, and was attached directly to said eccentric. 
The eccentric-rod of the main-valve gear works horizon- 
tally, while the cut-off eccentric-rod inclines dow^nward, 
so that its attachment to its rocker-arm may be on a level, 
or nearly so, with the centre line of the main rock-shaft. 
This arrangement is shown in the cut on page 52. 

The stem of the cut-off valve passes through the hollow 
stem of the main valve, and is connected to an upright 
arm on the cut-off rock-shaft, on the end opposite to that 
to which the eccentric-rod is attached. The automatic 
adjustment of the cut-off eccentric is effected by means 
of its connection with two weighted levers contained in a 
circular case on the engine-shaft. The outward move- 
ments of these levers advance the eccentric forward on 
the shaft, and two well-tempered cast-steel wire-coil springs 
furnish the centripetal force which returns them when the 
speed slackens. The effect of this arrangement is such 
that the varying changes of speed due to load and press- 
ure, are almost imperceptible. 

All the wearing parts of these engines are made of the 
best material, and are proportionally equal to those of 
the most approved class of engines. The piston- and valve- 
rods, wrist- and crank-pins are made of cast-steel, and the 
connecting-rod and pillow-block boxes are of best machine 
brass and Babbit-metal. 



HAND-BOOK OF LAND AND MARINE ENGINES. 151 

WHEELOCK'S HIGH-PRESSURE ENGINE * 

The bed -plate of this engine is of a pattern very com- 
mon in use, and forms a but-joint with the cylinder like 
that of the Corliss and Allen types of engine. 

The steam is admitted and exhausted by a single valve 
at each end of the cylinder. 

The valves, like those of the Corliss engine, are sus- 
pended in sleeves or bushings, and are located at each end 
and directly under the cylinder, by which arrangement 
the clearance is reduced to a very small amount. 

The valve-gear is constructed in the simplest form of 
the ordinary eccentric-rod and wrist-pin, and can be at 
any time disengaged without difficulty. Motion is im- 
parted to the valves by cranks keyed into the stems, simi- 
lar to those on the Corliss valves, which, being securely 
fastened, make any derangement of the valves inside im- 
possible ; while the uniformity of wear is secured by the 
surfaces passing entirely over each other at every revolu- 
tion of the engine. 

By a peculiar arrangement of screw and check-nut, which 
form a joint or shoulder on the valve-stem, the necessity of 
stuffing-boxes is entirely obviated. 

The steam -chest being located underneath, and form- 
ing a part of the cylinder, serves as a reservoir, in which 
the drips are located, thus guarding against any injury 
that might otherwise arise from the accumulation of water 
in the cylinder. These engines are in very general use, 
and are said to give universal satisfaction. 

THE CORLISS HIGH-PRESSURE ENGINKf 

This engine has a massive bed-plate, which rests on cast- 
iron legs bolted to the pillow-block and cylinder, one end 
* See page 71. t See page 126. 



152 HAND-BOOK OF LAND AND MARINE ENGINES. 

of which forms the front head of the latter. They have 
also large fly-wheels, which serve the double purpose of a 
balance-wheel and driving-pulley. 

There are four valves, two steam aud two exhaust, placed 
at the extreme ends and directly upon the bore of the cyl- 
inder ; being made independently adjustable, it follows that 
the time of commencement, extent, and rapidity of the 
movement of each is capable of being arranged accurately. 

Motion is imparted to the valves by a single eccentric, 
acting through the medium of a vibrating disk, sometimes 
called a wrist-plate, from which the valve connections 
radiate. Apart from the simplicity of this device, an im- 
portant advantage is gained by the utilization of the crank • 
motion's known irregularity to give the valves a rapid 
motion at the instant of opening or closing. 

The steam-valves are placed on top of the cylinder and 
open directly into the clearance, therefore there are no 
long passages to fill w^ith steam at each end of the cylin- 
der. The same valve admits and cuts ofiT the supply of 
steam, no auxiliary valve being necessary. 

The exhaust-valves are situated under the cylinder, at 
the clearance spaces, and can therefore free the cylinder 
of water, without the use of other devices, in the most 
thorough manner. They, like the steam-valves, are situ- 
ated close to the bore of the cylinder, and therefore have 
no long passages to fill with live steam. 

The steam-valve commences to open its port at one end 
of the cylinder when the eccentric is producing its most 
rapid movement, and, as the motion of the eccentric is de- 
clining towards the end of the throw, an increasing speed 
is obtained by means of the wrist-plate, which compen- 
sates for the slow motion of the eccentric. At the same 
time, the steam-valve at the opposite end of the cylinder 
commences to lap its port, by the motion of the eccentric, 



HAND-BOOK OF LAND AND MAKINE ENGINES. 153 

but by a reverse or subtraction of speed, produced by the 
same wrist-plate, which speed is constantly decreasing till 
the throw of the eccentric is completed. The lapping and 
opening of the steam-ports require each the same amount 
of throw of eccentric, producing, say, for instance, a lap 
of half an inch at one end of the cylinder, while the 
opposite end would have an opening of more than twice 
that amount. 

The exhaust-valves are moved by the same eccentric 
and the same wrist-plate before spoken of; but they have 
a much greater travel for the purpose of giving the engine 
a free exhaust. The exhaust-ports are as long and twice 
as wide as the steam-ports. 

At the commencement of each stroke, the full boiler 
pressure enters the cylinder, and the motion of the gov- 
ernor determines at each half revolution where the steam 
is to be cut off, that the proper speed may be maintained. 

HAMPSON AND WHITEHILL'S HIGH - PRESSURE 
ENGINE.* 

The cylinder of this engine is securely bolted to a heavy 
bed-plate, and the supports for the guides to the cross- 
head and the main pillow-block are cast on the bed. A 
stout wrought-iron brace is placed between the main pillow- 
block and the exhaust-valve chest. 

The steam-chests, as shown in the cut, are bolted to the 
cylinder on one side and the exhaust-chests on the other ; 
the steam- valves are horizontal poppet, and are operated 
by cams on the governor-spindle ; while the exhaust-valves 
are plain slide, double-ported, and receive their motion 
from an eccentric on the main shaft, which gives them a 
quick and large opening. They are connected to the valve- 
stems in such a manner that the wear on the face and 
* See page 154. 



154 HAND-BOOK OF LAND AND MARINE ENGINES. 




uj VH 



HAIs^D-BOOK OF LAND AND MARINE ENGINES. 155 

seats is taken up by tha steam acting on the backs of the 
valves. The lower edges of the exhaust-ports are below 
the line of the bore of the cylinder, which facilitates the 
escape of the water of condensation from the cylinder and 
exhaust-chests. 

The governor is of the ordinary centrifugal, ball kind, 
and is claimed to be more powerful, less liable to get out 
of order, and to control the speed of this class of engines, 
better than any other form now in use. It receives a posi- 
tive motion from a pair of mitre-gears on a horizontal 
shaft connected with the main shaft of the engine. 

The valves are readily accessible by simply removing 
the bonnets of the steam- and exhaust-chests, and, as all 
parts of the valve-gear are expqsed to view, any derange- 
ment can be easily detected. The expansion-gear is what 
is known as Penny's automatic cut-off. 

A very high economy in the use of steam is attained in 
these engines. 

THE ALLEN HIGH-PRESSURE ENGINE. 

The Allen engine (a cut of which is shown on page 
161) is based on the principle that work should be per- 
formed by the development of high velocity in a small 
mass ; consequently, the fly-wheel is of much less magnitude 
than is used on engines of equal power. 

The main bed-plate extends from the front cylinder- 
head, to which it is bolted, to a point sufiiciently beyond 
the crank-shaft for receiving the large pillow-block of the 
same. This bearing is made unusually long, and thus in- 
sures absolute rigidity of the shaft. 

There are two valve-chests on the side of the cylinder — 
one for the valves regulating the steam, the other for 
those controlling the exhaust. The former valves are 
rectangular, and work between scraped surfaces. They are 



156 HAND-BOOK OF LAND AND MARINE ENGINES. 

balanced by the pressure of the steam on their opposite 
sides, while the latter are of the same construction as the 
ordinary flat slide-valves. 

All the valves are actuated by one stationary link. The 
motion is transmitted to those regulating the exhaust 
through a rocker having opposite arms ; the connecting- 
stem, being pinned rigidly to the top of the link, imparts 
an invariable action to the valves. The steam-valves 
have their stems attached to two other rockers, and these 
in turn have connecting-stems pinned to the sliding-block 
of the link. To this block the governor is connected, 
which, acting under an increased or diminished velocity, 
causes the block to traverse the link, and effects an earlier 
or later cut-off* of the steam. 

In consequence of the high speed at which this engine 
is generally run, which is from 600 to 800 feet travel of 
piston per minute, it has been found advisable to use a 
solid piston having some grooves turned in it, in which 
the water of condensation from the first steam that enters 
the cylinder lodges, and forms a packing of sufficient re- 
sistance to prevent leakage. 

The crank- and wrist-pins and the piston- and valve-rods 
are invariably made of steel ; the guides and jaws of the 
cross-head are faced with the same material, and the boxes 
are usually made of bronze or gun-metal. 

WOODRUFF & BEACHES HIGH-PRESSURE ENGINE. * 

The bed-plate of this engine is of the ordinary form, 
cast in one piece, and is bolted to the foundation by means 
of an inside flange. The cylinder is bolted and dowelled 
to the bed-plate, which prevents the possibility of it being 
moved from its original position. 

* See page 165, 



HAND-BOOK OF LAND AND MARINE ENGINES. 157 

The steam-valves are conical or poppet, and receive a 
horizontal motion from a cam on the governor -spindle, 
which regulates the amount of opening according to press- 
ure and speed, the closing of the valves being effected by 
spiral springs enclosed in sleeves on the ends of the steam- 
chests. The governor rests on a shell above the steam- 
chests, directly in the centre of the cylinder, and receives 
a positive motion from a horizontal shaft driven by a 
spur-gear on the main shaft of the engine. 

The steam- valves are located at each end of the cylin- 
der, and open directly into the clearance, thus reducing 
the cubic contents of the steam passages. The exhaust- 
valve is an ordinary flat slide, situated below the bore of 
the cylinder, and is operated by a double crank of shore. 
throw, which receives its motion from a pair of mitre-gears 
on the same horizontal shaft that works the governor. This 
arrangement admits of a free exhaust with a very limited 
travel of valve, and also allows an easy escape for the 
water of condensation from the cylinder. This form of 
exhaust-valve is somewhat objectionable, as the w^ar is 
entirely on its back, consequently the pressure of steam 
against its face has a tendency to force it away from its 
seat, and induce leakage. 

These engines, like most automatic cut-off engines, are 
capable of developing a great amount of power, as the 
steam is admitted and exhausted very freely, thus prevent- 
ing the possibility of much back pressure. 

NAYLOR'S VERTICAL HIGH-PRESSURE ENGINE.* 

The design of this engine is very creditable, for, while 
it possesses strength and solidity, there are only three prin- 
cipal parts — the cylinder, frame, and circular base. The 
slides and the pillow-blocks are cast with the frame, so 
14 * See page 300. 



158 HAXD-BOOK OF LAXD AND MARINE ENGINES. 

that they cannot become loose, and in consequence of their 
vertical position, the side wear of the cylinder, cross-head, 
and guides is very slight. 

The piston-rod, crank- and wrist-pins, and valve-stem 
are made of steel, and all the bearing surfaces are large 
and well fitted ; the adjustment for taking up the wear in 
the revolving parts is made in the most approved manner. 
The running gear is accurately balanced, so that a very 
high piston speed may be attained without any vibration 
or jar. 

The cross-head has adjustable gibs, turned to fit the 
guides, which are bored out exactly with the line of the 
cylinder. The cylinder is handsomely lagged with black 
walnut and banded with brass, and the glands and stuflSng- 
boxes are made of the latter material and nickel-plated. 
The valve is the ordinaiy expansion-slide, but Cooper's 
patent balanced slide-valve is used when required. The 
speed of the engine is controlled by an improved governor, 
manufactured at the same works. 

WILLIAMS' VERTICAL THREE-CYLINDER HIGH- 
PRESSURE ENGINE.* 

In this engine three cylinders are used, and each cylin- 
der is single-acting, receiving the steam upon the upper 
side only of the piston. The connecting-rods are attached 
directly to the pistons, and actuate a three-throw crank- 
shaft. 

Each piston serves as a steam-valve, and controls the 
supply of steam to one or the other of the two remaining 
cylinders. There is a steam chamber in each piston, and 
a port in its side. Steam is supplied from the boiler by 
means of a tube passing through the top of the cylinder 
and into a steam-chest. 

When the piston has reached about three-fourths of it^ 
*See page 319. A 



HAND-BOOK OF LA>sD AND MARINE ENGINES, 159 

downward stroke, the steam -port in it overlaps a port 
formed in the side of the cylinder, and steam then passes 
to the top of another of the cylinders. When, on the other 
hand, the piston has reached about one -half its return- 
stroke, it uncovers the port in the «ide of its cylinder, and 
allows the steam to escape from the cylinder, into which it 
was previously admitted, into a casing round the crank- 
shaft, from which the exhaust-steam is taken either to a 
condenser or to the air, as the case may be. 

The advantages claimed for this class of engines are 
cheapness, simplicity of construction, fewness of parts, and 
an almost unlimited speed. But while it may be admitted 
that the w^hole arrangement is simple and compact; yet it 
is difficult to see what advantage can be gained by its use, 
over that of the double-acting arrangement, as, when the 
cylinders become worn or the pistons leaky, they involve 
the expense of reboring three cylinders, or readjusting 
three pistons ; for, unless they are perfectly steam-tight, 
they must continue to be a great source of annoyance. 

ROPER'S CALORIC ENGINE. 

The cut on p. 324 gives an elevation of Roper's* caloric en- 
gine, showing the valves, valve-gearing piston, cylinder, air- 
pump, beam, and fly- and band-wheels. The cut on p. 325 
shows a vertical section of the same, in which No. 1 rep- 
resents the piston, on the top of which is fastened a leather 
packing; 2, the piston-drum, made sufficiently long to 
keep the packing from the fire ; 3, a lining of asbestos 
filled in between the shell and the sheet-iron lining w^hich 
surrounds the fire-brick ; 4, the brick lining of the fire- 
box ; 5, the outer shell of the engine ; 6, an iron ring to 
fasten the packing to the piston-head. 

- The writer is not the inventor. 



160 HAND-BOOK OF LAND AND MARINE ENGINES. 

To start the engine, it is only necessary to turn the 
fly-wheel half a revolution, in order to give the plunger 
of the air-pump an upward motion, when the cold air is 
drawn in at the opening, A; on the return of the plunger, 
the valve, B, closes, and the air is forced into the engine 
through the check-valve, D. 

If the lower damper, E, is open, and the upper damper, 
H, is closed, all the air will enter the fire-chamber under 
the grate, F, and pass through the fire. If the upper 
damper, H, is open, and the lower damper, E, is closed, as 
they should always be after the fire is in good condition, 
the air all passes over the fire. 

The expansion takes place in the fire-box, and, the d9ors 
being closed air-tight, the air remains under pressure until, 
by the eccentric motion communicated to the valve-toes, 
the inlet poppet-valve is opened, which allows the com- 
pressed air to pass into the cylinder, which forces the 
piston up; its place in the fire-chamber being supplied with 
cold air at the same instant by the downward movement 
of the air-pump plunger. 

At this moment, by the same motion, the outlet or ex- 
haust-valve is opened, and the inlet-valve closed. The 
force of the balance-wheel and the weight of the piston 
bring the piston back ; and the expanded air, returning by 
the same passage, finds the inlet-valve closed and the out- 
let or exhaust-valve opened, and is discharged through 
the funnel or chimney. 

Many of the mechanical difficulties heretofore expe- 
rienced in the employment of this class of motors seem to 
have been successfully overcome in this engine ; but still 
there are natural difliculties which neither chemistry nor 
mechanical science have been able to remove up to the 
present time, nor is it at all likely that they ever will be. 

The first great drawback to the use of heated air is the 



HAKD-BOOK OF LAND AND MARINE ENGINES. 161 




14* 



162 HAND-BOOK OF LAND AND MARINE ENGINES. 

small amount of its expansion. Water expands 1700 
times; so that to obtain a volume of expansion of 1 cubic 
foot, it is only necessary to force into the boiler 1 cubic 
inch of water. Now, could air be obtained in any simi- 
larly condensed and manageable form, yet retaining its 
present small capacity for heat, it would stand on a totally 
different footing from that which it actually occupies. 

Even at 568°, (which is probably above the temper- 
ature at which it could be practically used with advantage 
in a cylinder with air-tight piston,) its volume is only 
double what it is at GO"^ ; consequently, for every volume 
of heated and expanded air which develops power as it 
escapes, half a volume of cold air must be forced into the 
reservoir where the heating and expansion are accom- 
plished. 

This operation at once consumes half the theoretic 
power of the engine, plus the friction of the supply cyl- 
inder with its valves and appendages, and increases its 
consumption of heat for duty to considerably more than 
double that of the steam-engine. 

The second great disadvantage under which an air- 
engine labors may be said to be included in the first. It 
is this : that the small degree of tension it is possible to 
employ, from the limit placed by the question of temper- 
ature, not only virtually precludes the employment of the 
principle of working expansively to any extent, but also 
entails the necessity of employing cylinders of an enormous 
and unwieldy size in proportion to the power obtained. 

By cutting oJff the steam when the piston of a steam- 
engine has made | of the stroke, its duty may be in- 
creased more than threefold, reducing the consumption of 
fuel to 33 per cent. 

Now, suppose expansion be carried sufficiently far in 
the air-engine to reduce its consumption of fuel to 33 per 



HAND-BOOK OF LAND AND MABINE ENGINES. 163 

cent., thus placing it on an equality with the steam-engine, 
with regard to the consumption of fuel in proportion to 
the amount of pressure exerted on the piston, the steam- 
engine would still possess an immense advantage over the 
air-engine in practical utility and convenience on account 
of the huge bulk of the latter. 

An air-engine capable of developing power equal to 
that of a steam-engine would require a working cylinder 
with an area from 20 to 50 times greater than that of the 
steam cylinder, together with an air-pump of at least two- 
thirds the area of the working cylinder. 

Nevertheless, the caloric engine, in its present improved 
form, has for some years past been successfully employed 
as a hoisting-engine in stores and warehouses, and also as 
a pumping-engine at railway stations, hotels, and country 
residences. It is also desirable for yachts and agricul- 
tural purposes, on account of its simplicity and freedom 
from explosion. 

HASKIN'S VERTICAL HIGH-PRESSURE ENGINE.* 

This engine possesses some very excellent features, such 
as graceful design, compact, simple and perfect mechanism. 
The conical upright frame is bolted firmly to a base of 
considerable area, which in turn is bolted to the founda- 
tion ; the cylinder and steam-chest are neatly lagged and 
banded with brass. The openings to receive the brasses 
in the stub-ends of the connecting-rod are cut out of the 
solid forging ; the cranks are perfectly counterbalanced ; 
the crank-pin, cross-head wrist, piston-rod, valve-stem, etc., 
are all made of cast steel ; the bearing surfaces are univer- 
sally large, which prevents the possibility of rapid wear or 
excessive heating at any speed to which they may be sub- 
jected. The cross-head guides and pillow-block are cast 

* See page 308. 



164 HAI^B-BOOK OF LAND AND MARINE ENGINES. 

with the frame, so that they cannot become loose or out 
of line. The guides have concave surfaces for the cross- 
head to slide against. In fact, these engines are noted for 
their splendid proportions, compactness, and economy. 
Their speed is regulated by the Waters and Crowther's 
governor. 

MASSEY'S ROTARY ENGINE * 

It has been far more frequently the fortune of inventors 
of rotary engines to fail than to succeed. So frequently, 
indeed, and from so many various causes, has this been 
the case, that most engineers adhere to the opinion that 
the reciprocating engine can never enter into successful 
competition with the rotary, much less prove a formidable 
rival. And it is true that until quite recently no rotary 
engine had been produced that could approach in economy 
of power the best types of reciprocating engines. This 
might be attributed to the large amount of clearance, and 
to the great friction on the journals and packing, and also 
the leakage caused by wear. 

But the difficulties heretofore experienced in the con- 
struction and use of the rotary engine — that of keeping 
them thoroughly steam-tight without undue friction, and 
that of working steam expansively with a variable cut-off, 
and without undue clearance — have, it is claimed by the 
inventor of this engine, been successfully overcome. 

The advantages claimed for the rotary over the recipro- 
cating engine are cheapness, lightness, simplicity of parts, 
compactness, and occupying only a minimum -of floor 
space. The rotary engine, in consequence of its prompt 
reversing and capability of holding the load, is especially 
adapted as a bolster for mines and elevators. Besides, it 
is well suited for working the steering-gear of vessels. 

The rotary engine is desirable for locomotive, marine, 
* See page 333. 



HAND-BOOK OF LAND AND MARINE ENGINES, 



165 




■m 



166 HAND-BOOK OF LAND AND MARINE ENGINES. 

and stationary purposes, as, when well constructed, one 
rotary engine can be made to do the work of two recipro- 
cating engines, for in the rotary there are no dead centres 
or variations in leverage, etc. But still the question, as to 
what extent the rotary engine can cope with the rotative 
engine of corresponding power in economical use of steam 
alone, cannot at present be determined with accuracy, but 
must be left for future decision. 

PORTABLE ENGINES. 

By a portable engine is meant a steam-engine so 
arranged that it may be carried with facility from place 
to place entire, in a condition for use, either on wheels of 
its own, or upon a wagon or other conveyance. 

It differs from a stationary steam-engine in that the 
boiler and the engine, with all intermediate and subsidiary 
parts, are connected together in a compact manner, so as 
to require no other than their mutual support. While in 
the stationary engine, the boiler requires a foundation and 
setting of its own, the engine requires a separate foundation, 
generally with a detached support for the back end of the 
main shaft ; and not unfrequently the force-pump is apart 
from the engine, requiring also its independent foundation 
and source of motion. ^ 

HOW TO BALANCE VERTICAL ENGINES. 

When a vertical engine runs slow, the weight of the 
piston and piston-rod, cross-head, connecting-rod, and 
crank-pin must be counterbalanced, so that it will stand 
still in. any position ; but when the speed is very high, it 
will be only necessary to counterbalance such parts as 
revolve round the centre of the shaft, the crank-pin, the 
stub-end, and half the connecting-rod. Very accurate 
counterbalances must in all cases be determined by trial 
and experiment. 



HAND-BOOK OF LAND AND MARINE ENGINES. 167 

KNOCKING IN ENGINES. 

The causes of knocking in engines are very numerous, 
and while some of them will yield to an industrious and 
careful search, others will prove a puzzle alike to the 
engineer and the expert. Instances are not uncommon 
where weeks have been devoted, and engines taken all 
apart and put together again, to find the cause of a knock, 
when perhaps it was finally discovered to be caused by a 
loose crank-pin or key in a fly-wheel. 

Knocking, in many instances, arises from looseness in 
the boxes and joints, which strike each other whenever 
their motion is arrested. Knocking arising from this 
cause can be easily remedied by taking up the lost mo- 
tion. In many instances, shoulders become worn in the 
cylinder in consequence of the piston-rings not overlap- 
ping the counter-bore at each end of the stroke. In such 
cases any adjustment of the piston-packing or keys fs gen- 
erally followed by a knock in the engine. The most prac- 
ticable remedy for knocking arising from this cause would 
be to rebore the cylinder. 

Knocking is caused in some cases by steam being ad- 
mitted to the cylinder too late to take up the lost motion 
when the crank is passing the centre; while in others, 
in consequence of excessive lead, the steam is admitted too 
soon and too rapidly, which produces excessive cushioning, 
and causes the engine to thump. 

Engines frequently knock in consequence of the exhaust 
opening too late and closing too soon. The whereabouts 
of knocks arising from this cause are generally the most 
difficult to determine; and it not unfrequently happens 
that, after all ordinary means have been resorted to in 
vain, the indicator has to be applied in order to determine 
the precise location of the knock. 



168 HAND-BOOK OF LAND AND MARINE ENGINES. 

Engines out of line generally knock sideways at certain 
points of the stroke. The knocking heard in cylinders 
may be produced by a loose follower-plate or piston-rod ; 
while the noise in steam-chests is generally due to lost 
motion in the valve connections. Engines in very good 
condition sometimes knock in consequence of the packing 
being too hard or too tight around the piston-rod. There 
are a hundred other causes of knocking which the indus- 
trious engineer will be called upon to discover, and while 
most of them, as before stated, will yield to an easy search, 
some will try him severely. In fact, to discover knocks, 
he must see with his ears and hear with his eyes, 

THE INJECTOR. 

Of all the inventions of the mechanic and the scientist, 
nothing seemed to the uneducated to approximate so 
nearly to perpetual motion as the instrument now in 
general use as a boiler-feeder on locomotives and station- 
ary engines, and known as the injector, and which, from 
common use, no longer excites the wonder even of those 
who do not understand its mode of operation. It consists 
of a slender tube, through which steam from the boiler 
passes to another or inner tube, concentric with the first. 
The latter tube conducts a current of water from a pipe 
into the body of the injector. Opposite the mouth of this 
second tube, and detached from it, is a third fixed tube, 
open at the one end, facing the water supply-pipe and 
leading from the injector to the boiler. 

When the instrument is ready for use, the steam and 
water supply-pipes being fitted with stop- valves, and the 
feed-pipe to the boiler with a check-valve, by simply 
opening the steam-valve steam enters the small steam- 
pipe and rushes out at its extremity, picking up the 
whole stream of water, leaps across the open space with a 



HAND-BOOK OF LAND AND MARINE ENGINES. 169 




15 



170 HAND-BOOK OF LAND AND MARINE ENGINES. 

loud hissing noise, and plunges with its burden of -water 
into the open end of the feed-pipe at a tremendous velocity. 

Thus it will be seen that the steam that was admitted 
to the injector from the boiler returns to the boiler, carry- 
ing with it more than twenty times its weight of water. 
Not a drop of water is lost — not a particle of steam 
wasted. 

The principle on which the injector acts is that which 
was discovered by Venturi, in the beginning of the pres- 
ent century, and is known or designated as the lateral 
action of fluids. The action is somewhat identical to that 
of the steam-jet in locomotive boilers, — steam being ad- 
mitted to the inner tube of the injector, and the central 
conical valve being withdrawn, the steam escapes in a jet, 
near th6 top of the inlet water-pipe. 

If the level of the water be below the injector, the 
escaping jet of steam, by its superficial action (or friction) 
upon the air around it, forms a partial vacuum in the inlet- 
pipe, and the water then rises in virtue of the external 
pressure of the atmosphere. Once risen to the jet, the 
water is acted upon by the steam in the same manner as 
the air had been seized and acted upon in first forming 
the partial vacuum into which the water rose. 

The velocity with which steam flows into the atmosphere 
at a pressure of 60 pounds to the square inch is about 1700 
feet per second. Now let us suppose that steam is issuing 
with the full velocity due to the pressure in the boiler, 
through a pipe an' inch in area, — the steam is condensed 
into water at the nozzle of the injector, without suflfering 
any change in its velocity. From this cause its bulk will 
be reduced, say 1000, and therefore its area of cross-sec- 
tion — the velocity being constant — will experience a 
similar reduction. It will then be able to enter the boiler 
again by an orifice jo^o o^^i P^^^ <^f tl^at by which it escaped, 






HAND-BOOK OF LAND AND MARINE ENGINES. 171 




172 HAND-BOOK OF LAND AND MARINE ENGINES. 

Now it will be seen that the total force expended by the 
steam through the pipe, on the area of an inch, in expel- 
ling the steam jet, was concentrated upon the area jo^oo^b 
of an inch, and therefore was greatly superior to the oppos- 
ing pressure exerted upon the diminished area. 

The injector, as a boiler-feeder, has the advantage of 
occupying but little space, and can be set in almost any 
position ; is free from that objectionable knocking so com- 
mon in pumps where they work against pressure ; is not 
liable to get out of order; requires no belt, oil, or packing, 
and obviates the necessity, under many circumstances, of 
running the engine for the purpose of pumping water 
into the boiler. It is also of great value on locomotives 
in cases where the train is detained on the road or at rail- 
way stations. 

METHOD OF WORKING THE SELF-ADJUSTING IN- 
JECTOR WHEN REQUIRED TO LIFT THE WATER. 

1st. See that steam-plug, B (see cut on page 171), is 
closed down, and waste-valve stem, K, is raised. 

2d. Admit steam from boiler to injector slowly, which 
should cause the water to flow from pipe, P. 

3d. Turn up the steam-plug, B, until the waste- valve, K, 
can be closed without causing the injector to cease working. 

4th. Turn the steam-plug, B, up to increase the delivery, 
and down to decrease it. When the water flows to the 
injector, it can be started and stopped without closing 
down the steam-plug, B. 

A failure to work will always be indicated by an escape 
of steam and water from the waste-check, C, between water- 
supply and waste-pipe. 



HAND-BOOK OF LAND AND MARINE ENGINES. 173 

METHOD OF WORKINa THE ADJUSTABLE INJECTOR 
WHEN REQUIRED TO LIFT THE WATER. 

1st. Screw in steam-spindle. 

2d. Turn handle on side of injector, so that pointed end 
will be towards boiler end pf injector. 

8d. Turn on the water, if it is supplied under pressure. 

4th. Open wide the steam-valve, so as to give full head 
of steam. 

5th. Screw steam-spindle out all the way. 

6th. Turn pointed handle on side of injector until dis- 
charge from overflow stops. 

7th. To reduce quantity of water discharged, screw in 
steam-spindle, and stop any discharge at overflow by ad- 
justing pointed handle. 

When the instrument has been set to feed a proper 
amount, it may be stopped and started by opening the 
water-cock and steam-valve, without moving the steam- 
spindle or pointed handle on the injector, provided the 
water flows to it. If the water is lifted from a tank or 
well, follow instructions as given above. 

INSTRUCTIONS FOR SETTING UP INJECTORS. 

It is of the utmost importance that great care be taken 
in setting all kinds of injectors ; and there are some par- 
ticulars that may be mentioned as holding in common 
with all kinds of injectors. 

All pipes, whether steam, water-supply, or delivery, must 
be of the same internal diameter as the hole in the cor- 
responding branch of each injector, and as short and 
straight as practicable. 

When floating particles of wood or other matter are 
liable to be in the supply-water, place a wire screen over 
the receiving end of water-supply pipe, taking care to have 
15* 



174 HAND-BOOK OF LAND AND MARINE ENGINES. 




HAND-BOOK OF LAND AND MARINE ENGINES. 175 

the meshes as small as the smallest opening in the deliv- 
ery-tube, and the total area of meshes much greater than 
the area of water-supply pipe, to compensate for the closing 
of some of them by deposit. 

The steam should be taken from the highest part of the 
boiler, to avoid priming, but should not be attached to the 
steam-pipe leading to an engine, unless this pipe is large ; 
sudden variations in pressure may break the jet in the 
adjustable injectors, and would produce a constant move- 
ment of the piston in the self-adjusting. 

When any injector, capable of raising water, is set so as 
to lift the water, care must be taken to have the pipes very 
tight, so as not to draw air; and it is of importance that 
in any arrangement of the instrument, the water-supply 
should be unmixed with air, which will cause a sputtering 
sound, and is liable to break the jet. 

If the water is not lifted by the injector, but flows to it 
from a tank or hydrant, there should be a cock in the 
water-supply pipe. 

There must always be a stop-valve or cock in the steam- 
pipe between the steam space in boiler and injector, and a 
check-valve between the water space of boiler and the 
injector. 

After all the pipes are properly connected to the in- 
jector and boiler, and before admitting steam to the in- 
jector, it should be disconnected again from the pipes at 
the three union joints, and the steam and water should be 
allowed to flow through the pipes, to remove any red lead, 
or scale, and other solids from the interior of the pipes. 
This precaution will avoid trouble at first starting, which 
otherwise is liable to occur. 

In addition to the above, certain precautions must be 
taken in setting the self-adjustable injector. There must 
be in the water-supply pipe an alarm check- valve, with 



176 HAND-BOOK OF LAND AND MARINE ENGINES. 

waste-check attached ; and, when fed with water under 
pressure, any considerable pressure in the water-supply 
pipe must be avoided. But when unavoidable, and the 
pressure in the supply-pipe is too great, a regulating stop- 
valve must be used. 

In determining the position of an injector, it must be 
borne in mind that the instrument may be placed verti- 
cally, horizontally, or at any angle, as most convenient. 
In some cases, when used without steam-spindle, it may 
be found convenient to place it upside down. 

For locomotives, the injector should be placed in pref- 
erence on the right-hand side of the engine, in the most 
convenient position for being operated. When placed so 
low down that the water from the tank will at all times 
flow to it, the instrument is more readily started, for in 
such case the regulation for quantity can be made by the 
steam -spindle, which afterwards need not be moved, but 
the instrument can be started by merely turning on the 
water from the tank, opening the starting-valve at the 
boiler, and closing the waste-valve. 

TEMPERATURE OP FEED-WATER. 

Maximum temperature of feed admissible at different 
pressures of steam. 

Pressure of steam, lbs. per sq. in., 10, 20, 30, 40, 50, 100. 
Temperature of feed, Fahrenheit, 148°, 138°, 130°, 124°, 120°, 110°. 



HAND-BOOK OF LAND AND MARINE ENGINES. 177 



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178 



HAND-BOOK OF LAND AND MARINE ENGINES. 



PUMPS. 

The annexed cut represents an ordinary lift- and force- 
pump, with trunk-plunger and two valves, the pipe from 

one leading to the well or cistern, 
and from the other to the boiler 
or tank. 

In the ascending stroke of the 
plunger the lift-valve is opened ; 
and, if the air be expelled from 
the barrel of the pump and the 
pipe, the water will follow the 
plunger in its ascent to a height 
of 34 feet above the level of the 
water in the well. In the de- 
scending stroke, the lift-valve is 
closed by the compression of the 
water in the barrel of the pump, 
caused by the downward movement of the plunger, which, 
at the same time, causes the discharge valve to open, 
and forces the water out into the boiler or tank. 

A belief or an idea very generally prevails among en- 
gineers and others, that water is lifted by means of what 
is termed " suction ; " but this is a grave error, as there is 
no such thing as " suction." The principle on which water 
is raised is, that the air being expelled from the tube and 
a partial vacuum formed, the pressure of the air on the 
outside of the tube forces the water up nearly 34 feet, or 
the height of a column of water that would balance the 
average pressure of the atmosphere. 

As water expands by heating, a pump that would be 

large enough to furnish a given quantity of cold water, 

would not be of sufficient capacity if the water was heated. 

When it becomes necessary to pump hot water, it is 




HAND-BOOK OF LAND AND MARINE ENGINES. 179 

always best to have the supply above the pump, as it is 
very difficult to raise hot water. 

Boiler feed-pumps should, in all cases, have a capacity 
equal to one cubic foot of water per horse-power per 
hour. 

It frequently happens that when pumps, to all ap- 
pearances, are performing well, the water does not rise in 
the boiler or tank, but gradually falls below the level 
at which it stood when the pump was started. Such evi- 
dence shows conclusively that one of^two things is amiss: 
either that the water does not enter the boiler, or that it 
escapes through some other opening. 

In order to arrive at some definite conclusion as to the 
cause of the difficulty, the first thing to be done, is to ex- 
amine the check-valve, and see if it is in operation ; this 
can be proved by applying the ear to the valve, and as- 
certaining if it rises and falls at each stroke of the pump : 
the action of the valve can also be determined by apply- 
ing the hand to the feed-pipe below the valve. 

Should the check-valve be found to be all right, the 
next step would be to examine the blow-oflT cock and all 
the outlet valves ; the pump should also be examined, in 
order to ascertain if it is hot, as feed-pumps cannot de- 
liver water very hot, for the reason that the vapor gener- 
ated in the pump-chambers prevents the induction-valve 
from opening to admit the cold water, and create a partial 
vacuum in the pump. 

Pumps located near boilers are very liable to become 
hot.; and, in such cases, if the pump should fail to lift, the 
pet-cock in the pump-cylinder should be opened, in order 
to allow the hot water in the pump-barrel to run out and 
lessen the pressure, when it will be found, in most cases, 
that the pump will lift. 

The most general causes of failure of pumps to act are, 



180 HAND-BOOK OF LAND AND MARINE ENGINES. 

leakage in the pipes, wear in the packing of the steam- 
and water-cylinders, the valves not closing when expanded 
by heat, or their being kept from their seats by mud or 
other impurities in the water ; the pipes becoming choked 
with incrustation, lime, salt, and such mineral substances as 
are commonly found in spring, river, and sea water. 

All pumps, whether of hot or cold water, bilge, inde- 
pendent, or auxiliary, should be frequently examined and 
tried by being put in service, in order that they may be 
ready for any emergency that may arise. 

The piston- and valve-rods of all pumps should be fre- 
quently and carefully packed, as, when the packing becomes 
old and hard, it has a tendency to cut and flute the rods, 
which induces leakage, and eventually incurs the expense 
of having them renewed. 

Pumps should be kept perfectly clean and free from oil 
and dirt, as such accumulations detract very much from 
their general appearance, and interfere very materially 
with their working. 

STEAM-PUMPS. 

Steam-pumps may be said to be among the most essen- 
tial requisites of the age. They are used for boiler-feeders, 
extinguishing fires, pumping liquids, and, in short, for 
almost every variety of purposes in manufacturing and in 
civil and mechanical engineering. 

As boiler-feeders, they are superior to any other known 
invention, as they are available for pumping feed- water 
against extremely high pressures, and for keeping boilers 
supplied when circumstances require the stoppage of the 
engine. They can be regulated either to furnish a con- 
stant supply of water for boilers or other purposes, or the 
supply can be largely increased if it should be found 
necessary. 



HA$rD-BOOK OF LAND AND MARINE ENGINES. 181 




THE DAYTON CAM-PUMP. 

The annexed cut represents the Dayton cam double- 
acting steam-piston pump, which, it is claimed, is abso- 
lutely positive in its action, simple in construction, and 
economical in the use of steam. 

The principal feature is the mode of working the steam- 
valve by means of a cam bolted on the piston-rod, and 
16 



182 HAND-BOOK OF LAND AND MARINE ENGINES. 

moving with it. By the shape of this cam, the stroke is 
rendered slower at each end, thereby giving time for the 
water-cylinder to fill. 

A full stream is thus insured, and the pump is prevented 
from cushioning against the water when the cylinder is 
but half filled. 

The arrangement is such that the valve cannot be 
thrown into such a position as to shut off the steam and 
stop the pump. 

It will be seen that there are no dead centres, and that 
the action is absolutely positive, and that the arrangement 
of the cam movement, in connection with the piston, causes 
the water-valves to lift and set easily, and without jar, 
thereby saving the wear and tear of valves and seats. 

There are no small, intricate steam passages to fill up 
with dirt and grease, and the water-valve chambers may 
be easily opened to reach the valves. The- steam- valve, 
being of the plain slide description, is not liable to get out 
of order. 

This pump will start at any part of the stroke, and will 
lift either hot or cold water without change of valves. It 
can be used as a boiler-feeder or a fire- and marine-pump. 

The inventor of this pump seems to have studied all the 
requirements of a good pump, and avoided all the points 
of defect from a liability to wear or otherwise, thus ren- 
dering it one of the most simple, effective, and powerful 
pumps in the country. It furnishes another proof of the 
vast improvement that has been made in steam-pumps 
within the past few years. 

Rule for finding the Diameter of Pump-plungep for any 
Engine. — When the pump-stroke is J the stroke of the 
engine, the diameter of the steam-cylinder multiplied by 
0*3 will give the proper diameter of pump-plunger. 

Another Rule. — When the pump-stroke is i the stroke 



HAND-BOOK OF LAND AND MABINE ENGINES, 183 

of the engine, the diameter of the cylinder multiplied by 
•42 will give the proper diameter of pump-plunger. 

Diameter of pump-plunger should be- equal to i the ) 
diameter of the cylinder, when the pump-stroke is i the 
engine-stroke. 

Diameter of pump-plunger should be equal to i of the 
diameter of the cylinder, when the pump-stroke is i the 
engine-stroke. The velocity of water in pump passages 
should not exceed 500 feet per minute. Pump-valves 
should have an area of i the area of the pump. 

Feed-pumps for Condensing Engines. — For condens- 
ing engines, the diameter of the pump-plunger should equah~^ 
1*11 the diameter of the steam-cylinder when the pump- ■ 
stroke is i the engine-stroke, and |- the diameter of steam- I 
cylinder when the pump-stroke is i the stroke of the engine. 

Rule for finding the Necessary Quantity of Water pep 
Minute for any Engine. — Multiply the cubic space in cyl- 
inder in inches, to which steam is admitted before being 
cut off, by twice the number of revolutions per minute, 
and divide the product by the comparative bulk of steam * 
at the pressure used; the quotient will be the cubic 
inches of water required per minute. 

EXAMPLE. 

Diameter of cylinder, 12 inches. Area 113'09 sq. in. 

Stroke, 24 in. Steam cut-ofFat J stroke 12 in. 

Revolutions per minute 60 

Pressure per sq. in., 70 lbs. Cubic in. steam from 1 

cubic in. water 408 

113-09 

12 

1357-08 
120 



408) 162849-60 

399*14 cubic inches of water. 
* See Table on pages 39-43. 



184 HAND-BOOK OF LAND AND MARINE ENGINES. 

This rule takes into account the expenditure of steam 
only ; but, as is well known in practice, a large quantity 
of water passes from the boiler to the cylinder in mechan- 
ical combination with the steam, allowance must there- 
fore be made for such losses, also for the waste incurred 
by clearance in the cylinder, cubic contents of steam-ports, 
condensation, etc., so that in the selection of a pump for 
any engine, it is advisable that it should be of sufficient 
capacity to furnish at least twice the quantity of water 
designated by the rule. 

DIRECTIONS FOR SETTING DP STEAM-PUMPS. 

Pipes fully as large as the pump connections should be 
used in all cases, and where it becomes necessary to use 
long or crooked pipes, they should be even larger. 

The discharge-pipe should be the same diameter from 
the pump to the boiler, as any reduction in the diameter 
of a pipe greatly diminishes its capacity. 

A pipe two inches in diameter, 100 feet long, will de- 
liver but I the quantity a pipe 2 inches in diameter and 
2 inches long will with tlife same pressure. 

Short bends and angles in the pipe should be avoided 
as much as possible, as they retard the flow of the water ; 
but when they have, of necessity, to be used, they should 
be as large as practicable. 

Leaks in pump-pipes should be guarded against as much 
as possible, as a very small leak very often destroys the 
efficiency of a good pump. 

The exhaust-pipe of steam-pumps should be run down, 
when convenient, in order that the water of condensation 
may flow out instead of being forced out. 

Pumps of every inscription require more care in winter 
than in summer, and should receive particular attention 
in cold, frosty weather. All drip-cocks should be left 



HAND-BOOK OP LAND AND MARINE ENGINES. 



185 



open at night, in order that the water in the cylinder and 
supply-pipe may run out, and prevent the possibility of 
freezing. 




The Pulsometer, 



The conditions upon which the proper action of the 
pulsometer depends are similar, in all^essential particulars, 
to those which pertain to the management of the ordinary 
double-acting piston-pump. But although the pulsometer 



16* 



186 HAND-BOOK OF LAND AND MARINE ENGINES. 

may be operated under the same conditions as control the 
operation of piston-pumps ; yet the arrangements should 
be made with judgment and discretion, to meet the char- 
acteristic difference existing between the two systems, and 
with special reference to the nature of the fluid to be 
pumped. 

The pulsometep requires a free current of the fluid in 
an uninterrupted stream, as a necessary condition of its 
action. If the source of supply of the liquid be exhausted, 
or the induction passage is contracted so as to prevent its 
free admission in response to the vacuum impulses alter- 
nately created in the chambers above, the steam will blow 
through the discharge-pipe, and the pulsation wdll cease. 

The pulsometer is peculiarly adapted for pumping water 
from mines, foundations, or excavations where quicksand 
or mud occur, as it will pump water combined with fifty 
per cent, of mud or sand without any derangement of its 
parts, as there is no cylinder, piston, or valves to cut or 
wear. It can also be used to irrigate land, drain swamps 
and ponds. It is also available as a bilge-pump on board 
of vessels, as it is not liable to become choked with grain 
or other substances. The pulsometer will raise water or 
any other liquid from a depth due the vacuum produced by 
the condensation of steam, and will force the same to an 
elevation due the initial pressure of the steam in the boiler 
operating it. 

The pulsometep possesses many advantages in point 
of economy and convenience, as it can be lowered into deep 
wells or mining-shafts, and, in fact, set or hung up in any 
place most convenient to the work or the steam, and, like 
the injector, requires no oil, packing, adjustment, or special 
care in its management. 



HAND-BOOK OF LAND AND MARHSTE ENGINES. 187 



JAMES WATT. 
A name which must endure while the peaceful arts flourish 



188 HAND-BOOK OF LAND AND MARINE ENGINES. 

CONDENSING, OR LOW-PRESSURE STEAM-ENGINES. 

When a steam-engine is so arranged that the exhaust 
steam from the cylinder escapes into a condenser and is 
condensed into water, it is termed a condensing, or low- 
pressure engine ; because, by condensing the steam and 
producing a vacuum, not only is. the pressure of steam in 
the boiler, but also the 15 pounds per square inch required 
in the non-condensing engine to overcome the pressure of 
the air, rendered available as an effective force against the 
piston. 

Consequently, when a condensing engine is working 
steam of 10 pounds pressure per square inch by the steam- 
gauge, the effective pressure per square inch exerted on 
the piston would be 25 pounds if the vacuum is perfect, 
which in fact, it never is ; the average being about 12 
pounds, which, with the boiler pressure of 10 pounds, would 
exert an effective pressure on the piston of from 21 to 22 
pounds per square inch. 

In Watt's engines the ordinary working pressure was 
from 5 to 6 pounds above that of the atmosphere ; but the 
steam-valve remained open and allowed steam of the 
boiler pressure to follow the piston during the whole 
length of the stroke. Now, however, there are few con- 
densing engines run with less than from 20 to 25 pounds 
per square inch boiler pressure ; but the steam is generally 
cut off from the cylinder at one-half the stroke, and then 
allowed to expand during the remainder. 

It may be fairly assumed that a non-condensing engine 
has, on an average, at least two pounds per square inch 
back pressure on the piston. Some have much more than 
this, and first-class engines have less ; but two pounds can 
be considered a fair example of ordinary practice. By 
the application of the condensing principle, there would 



HAND-BOOK OF LA:N^D AND MARINE ENGINES. 189 

be a negative pressure of say 10 pounds per square inch 
on the back of the piston, so that the piston pressure 
would be increased by 12 pounds. 

Now, if the application of the condensing principle de- 
creases the back pressure, it is obvious that it must increase 
the positive pressure on the piston. It is plain, therefore, 
that a lower pressure of steam can be used, or, that the 
steam may be cut off at an earlier point of the stroke; the 
gain in either case can be approximately calculated. If 
the gain in positive pressure produced by the reduction in 
back pressure be multiplied by 100, and divided by the 
mean effective pressure, it will give the percentage of 
gain due to the effect of the condensing principle. 

It is tolerably safe to estimate the saving effected by the 
use of the condensing over the non-condensing engine at 
from 20 to 25 per cent, of the amount of steam used, and 
consequently the amount of coal consumed. It sometimes 
happens, however, that little or no saving is effected in the 
condensing engine ; but this loss is not in the principle, 
but is in nearly all cases induced by d^cts in the ma- 
chinery, which admit of a back pressure sufficient to 
counterbalance the effect due to the vacuum. 

To get the maximum of economy out of any class of 
expansive condensing engine, the press-ure of steam and 
point of cut-off must be so regulated that the steam passes 
into the condenser at the end of the stroke at a pressure 
not exceeding 5 pounds above a perfect vacuum ; and with 
steam at 45 pounds pressure above the atmosphere, which 
is equal to 60 pounds pressure above a perfect vacuum 
(the pressure of the atmosphere being considered as equal 
to 15 pounds on the square inch), and a terminal pressure 
of 5 pounds, we get 12 expansions, because the pressure at 
the end of the stroke is 12 times less than what it was at 
the points of cut-off. 



190 HAND-BOOK OF LAND AND MAEINE ENGINES. 

In condensing engines, the expenditure of steam — and 
therefore the performance — is generally estimated by what 
is termed the weight of sensible steam in the cylinders ; 
that is, the weight as shown by the indicator diagrams. 
This indication, in engines in which the condensation in 
the cylinders is limited by suitable conditions of action, 
may approach the real figure, so as to give results accurate 
enough in practice; still, in other cases, it gives results 
of no possible value. 

This weight of sensible steam in the cylinder difiers 
from the weight of water actually vaporized in the boiler, 
because it does not take into account the loss of steam by 
leakages, condensations in the pipes, or the dead spaces at 
the cylinder's ends, etc. Then, again, it is no uncommon 
thing to see the consumption of fuel indicated with the 
minutest accuracy in figures containing two or three deci- 
mals, and this without the slightest mention being made 
of the kind of fuel used ; though it is well known that the 
heating power of some kinds of coal is nearly, if not fully, 
twice that of others. 

EXPLANATION OP THE WORKING PRINCIPLES OP 
THE CONDENSING ENGINE. 

The steam-valve being opened, steam flows through the 
passage to the cylinder and forces the piston down or for- 
ward, as the case may be ; while, at the same instant, the 
exhaust-valve opens, and allows the steam that is in front 
of the piston, to escape through the exhaust-pipe into the 
condenser, where it mingles with the injection water* and 
is condensed into water, thereby forming a vacuum in 
front of the piston ; consequently, the whole pressure on 

* The steam mingles with the injection water in the jet-condenser only 
as it is condensed by being brought in contact with cold surfaces, when 
the surface-condenser is used. 



HAND-BOOK OF LAND AND MARINE ENGINES. 191 

the opposite side of the piston is effective pressure. When 
the piston reaches the end of the stroke, the steam-valve 
closes, and the opposite steam- and exhaust-valves open, 
the steam forcing the piston forward, as in the former 
case, and the exhaust steam escaping to the condenser. 

The condensed water which collects in the bottom of 
the condenser is drawn off through the foot-valve to the 
air-pump, and forced out through the delivery-valve into 
the hot- well, from which it is taken to feed the boilers or 
delivered overboard. Thus, it will be seen that the cir- 
culation from the boiler through the cylinder and con- 
denser to the hot-well, and back again to the boiler, must 
be continually kept up while the engine is in motion. 

A condenser and air-pump can be attached to any non- 
condensing engine, and it then becomes what is commonly 
known as a low-pressure engine. In this case the initial 
pressure of the steam can be reduced, or the valve may 
be altered so as to cut off the steam at an earlier point of 
the stroke; and the engine will still develop the same 
power as before. 

HORSE-POWER OP CONDENSING ENGINES. 

In Great Britain, every steam-vessel is rated at a certain 
nominal horse-power ; in the United States, on the con- 
trary, the dimensions of the cylinder are almost univer- 
sally expressed in feet and inches, the nominal power 
being considered of little moment, and the actual power 
being well understood to depend on the effective pressure 
in the cylinder, and the speed of the piston, both of which 
elements may be varied at will within certain limits. 

Watt's Rule for calculating the power of condensing 
engines is as follows: — "Multiply the square of the 
diameter of the cylinder in inches by the cube root of the 



192 HAND-BOOK OF LAND AND MARINE ENGINES. 

stroke in feet, and divide the product by 47 ; the quotient 
is the number of nominal horse-power." This rule sup- 
poses a uniform effective pressure upon the piston of 7 
pounds per square inch, and a piston-speed of 160 feet per 
minute. 

The following Rule is more applicable, however: 1st. 
Find the mean effective pressure in pounds upon the piston. 
2d. Find the pressure upon the piston, in pounds, necessary 
to overcome the friction of the engine, also that necessary 
to overcome the friction of the air-pump : deduct these 
two amounts from the whole mean effective pressure ; then 
multiply the remainder by the velocity of the piston in 
feet per minute. 3d. Find the atmospheric pressure in 
pounds upon the air-pump bucket and multiply it by the 
velocity of the air-pump bucket in feet per minute ; sub- 
tract this amount from the first product and divide the 
remainder by 33,000; the quotient will be the actual 
horse-power of the engine. 

The losses arising from the different causes are shown 
by the following table, the pressure of steam in the boiler 
being represented by 1 .000. 



Loss from velocity of steam into cylinder 

Loss through condensation of steam in cylinder and pipes 

Loss occasioned by passing through openings and pipes 

Loss occasioned by cutting off steam , 

Friction of piston, and loss by waste through packing 

Force required to move the different valves, and friction of bear- 
ings 

Power required to work the air-pumps 

Total loss 

Remainder 

Counter-pressure occasioned by vacuum 

Multiplier in full for resistance 



007 
016 
■007 
100 
125 

063 
050 

'368 
632 
063 
695 



This multiplier may be used in calculating the actual 



HAND-BOOK OF LAND AND MARINE ENGINES. 193 

power of all condeDsing engines from 100 to 2000 horse- 
power. 

EXAMPLE. 

Diameter of cylinder, 70 inches = Area, 3848*46 square inches. 

Stroke, 14 feet, } rJ^ ^ ^ • , 

No. of revolutions, 16, | = ^'^^^^ "^ P'^*°° P^' '^''"'^' ''^S feet. 

Pressure, 33 pounds per square inch. Cut oiF at 9 feet. 

14-^9 = 1-5 Hyperbolic Logarithm of 1*5 = 40546. 

1-40546 X 33 
•40546 + 1 = 1-40546. ^ = 30*92 mean pressure per 

square inch. 30*92 

3848*46 

118994*3832 

*448 



53409483-6736 

*695 

33,000 )37119591*1531520 

1124*83 horse-power. 

THE VACUUM. 

The literal meaning of the term "vacuum'' is space 
unoccupied by matter. The cylinder of a steam-engine 
filled with steam, though vaporized from a small quantity 
of water, cannot be said to be void of matter ; but con- 
dense that steam to its original bulk into water, and with- 
draw this water from the cylinder, and the space formerly 
occupied by the steam will be unoccupied. No matter 
remaining in the cylinder, there is what is termed a 
" vacuum," or a void space. 

We have supposed this operation to have taken place 
under the piston of a steam-engine, and in that case there 
is no resistance to be overcome in the descent of the piston. 

The pressure of the atmosphere alone, which is 15 
pounds to the square inch, or thereabouts, would suffice to 
force the piston down with a power equal to the degree of 
17 N 



194 HAND-BOOK OF LAND AND MAEINE ENGINES. 

vacuum formed up to the limit stated, — 15 pounds, if 
the vacuum be perfect. 

The first steam- and atmospheric-engine was con- 
structed on this principle : Steam being admitted below 
the piston in a cylinder with its upper end open to the 
atmosphere, which caused it to rise ; the steam being 
then condensed in the same cylinder by the application 
of cold water ; the piston being forced down oii the return- 
stroke by the pressure of the atmosphere alone. If steam 
be allowed to take the place of the atmosphere, as in 
Watt's engine, steam at atmospheric pressure will produce 
the same effect. 1700 cubic inches of steam, or one cubic 
inch of water converted into steam at atmospheric press- 
ure, will have a force sufficient to raise a weight of one 
ton one foot high ; two cubic inches of water, two tons ; 
and each additional ton, one cubic inch of water converted 
into steam. 

One of Watt's first improvements was to attach to the 
steam-engine a second vessel, in which to condense the 
steam. This he called a "condenser." He also enclosed 
the upper end of the cylinder with a cover, by which 
arrangement steam was admitted to each side of the piston, 
and made to answer a double purpose. And by connect- 
ing each side of the cylinder with the condenser, the 
condenser being supplied with cold water, the vacuum 
was very much improved ; thus the power of steam at a 
pressure above the atmosphere was made available, in 
addition to the pressure of steam below the atmosphere. 
By admitting the steam alternately on each side of the 
piston, after a partial vacuum had been formed in the con- 
denser, the engine was thereby made to be double-acting, 
and its power increased in proportion to the pressure of 
the steam above the pressure of the atmosphere. 

Steam arising from an open vessel, for instance, from 



HAND-BOOK OF LAND AND MARINE ENGINES. 195 

the man-hole of a steam-boiler, has a force greater than 
the pressure of the atmosphere, inasmuch as it has to dis- 
place the atmosphere before it can rise above the surface 
of the water. The resistance of the atmosphere is equal 
to about 15 pounds on the square inch. It varies from 
13 J pounds to upwards of 15 pounds ; on the average, it 
is about 141 pounds to the square inch. 2*037 inches of 
a column of mercury balance 1 pound pressure to the 
square inch. Therefore, steam enclosed in a steam-boiler, 
at 5 pounds pressure per square inch above the atmos- 
phere, or, in other words, at 5 pounds on the steam-gauge, 
is in reality a pressure of 20 pounds on the square inch, 
as applied to the piston of a steam-engine under the con- 
ditions above stated— taking the pressure of the atmos- 
phere at 15 pounds. If the pressure be less, as it often is, 
say 14 pounds, then the pressure upon the piston would 
be 19 pounds, because the resistance of the atmosphere on 
the safety-valve and steam-gauge would be less, and the 
steam in the boiler also less, in proportion to the reduced 
pressure of the atmosphere. 

Hence it arises that an engine heavily loaded varies in 
its speed with the varying pressure of the atmosphere. 
Suppose that the vacuum is not perfect, — and in practice 
it never is so,-— and that there remains in the cylinder a 
portion of uncondensed steam, the resistance of which is 
equal to 3 pounds to the square inch, then the steam on 
the upper side of the piston, at 5 pounds to the square inch 
above the pressure of the atmosphere, would act with an 
effective force of 17 pounds upon the square inch : the 
upper side of the piston having exerted upon it a pressure 
equal to 20 pounds to the square inch, and the under side 
a pressure or resistance equal to 3 pounds to the square 
inch. 

Under these circumstances, the condenser will have ex- 



196 HAND-BOOK OF LAND AND MARINE ENGINES. 

hausted steam from the cylinder equal to 12 pounds to the 
square inch, commonly termed a 12-pound vacuum ; and 
the uncondensed steam which has been left in the cylinder 
will have a resisting force equal to 3 pounds to the square 
inch. In proportion to the quantity of steam condensed 
to the whole, so is the value or available pressure upon 
the piston. If the uncondensed steam left in the cylinder 
was equal to 6 pounds to the square inch, then, in the 
other circumstances supposed, the available pressure 
upon the piston would be only 14 pounds to the square 
inch — a proof that vacuum is not power, as many are led 
to suppose. 

All power in the steam-engine is derived from the press- 
ure of the steam upon the piston. If there be no resist- 
ance on the other side of the piston, the whole pressure is 
available; when there is resistance, whatever be the 
amount, it has to be deducted. The available power of 
steam on the piston is what is left of the whole force when 
that deduction is made. All power from air, steam, or 
gas is the result of pressure or density ; and in proportion 
to the pressure so is the power. 

If 5 pounds more pressure to the square inch be added 
to the 5 pounds before described, the pressure of the steam 
above the atmosphere will be 10 pounds to the square 
inch, making the available pressure 25 pounds. Many 
suppose that by doubling the pressure above the atmos- 
phere, or double the pressure as shown by the steam- 
gauge, that the power of the engine is doubled. Such, 
however, is not the case ; for, though the pressure of the 
steam in the boiler above the atmosphere is doubled, they 
have only added 5 pounds to the 20 pounds already avail- 
able. This only gives 25 pounds to the square inch upon 
the piston of the engine, in place of 20 pounds. The in- 
creased power of the engine is as 25 is to 20, supposing 



HAND-BOOK OF LAND AND MAKINE ENGINES. 197 

the non-resistance, or, in other words, the vacuum, to be 
the same. In the practical working of engines, it is seldom 
that the full pressure in the boiler can be brought to bear 
upon the piston. To ascertain the real pressure operating 
on the piston at any given time, the indicator has to be 
resorted to, in the manner hereinafter explained. The 
foregoing conclusions have reference entirely to the con- 
densing ENGINE. 

Should the vacuum become impaired, which is often 
the case, the first thing to be done is to screw down the 
glands of the stuffing-boxes of the piston, air-pump, and 
expansion joints ; then hold a lighted candle near them, 
and observe whether the flame is drawn in or not. If all 
the joints are found to be tight, it is evident that the dim- 
inution in the vacuum is due to some other cause; 
perhaps an insufficiency of injection water, or some de- 
rangement of the foot- or delivery-valves. 

MARINE STEAM-ENGINES. 

The marine engine is one the construction of which 
is modified so as to enable it to be placed in a vessel, and, 
by working, to propel it through the water. In land 
engines the machinery is not, in general, limited in the 
space it occupies ; part of it may, if more convenient, be 
placed underground. This frequently happens with the 
condenser, air-pump, and cylinder. But it is quite differ- 
ent in the case of the marine engine, as the sleepers in the 
bottom of the vessel determine the depth at which the 
engine can be located, and the upper deck, in most cases, 
limits the height ; moreover, the less space occupied by 
the engine, the more can be devoted to the accommodation 
of the crew, passengers, and cargo. 

In considering the various engines proposed or in use 
17* 



198 HAND-BOOK OF LAND AND MARINE ENGINES. 

for marine purposes, either as respects form or detail of 
construction, the questions that most interest us refer to 
space occupied, accessibility of parts for cleaning, oiling, 
or repairing, loss of heat induced by radiation, degree of 
friction, tendency to jerk or jar, liability to be thrown out 
of line, free admission and escape of steam, lubricating 
arrangements, light and air in the engine-room, sufficient 
strength without excessive weight in any of the parts of 
the engine ; also the pounds of coal, per horse-power, per 
hour needed to run it. 

It is difficult to point out any position of the general 
duties of an engineer of more importance than the classi- 
fication of the machinery requisite for the hull of a vessel. 
How few consider what is due to those who, with untiring 
energy, devote time, money, and even health, to attain a 
given effect of mechanism. The mass, gazing on the com- 
plicated disposition of the component parts of a pair of 
marine engines, are merely mechanical observers. The 
position of a given lever or shaft, right or wrong, is all 
the same to them ; doubtless, the thought rarely, if ever, 
enters their mind that the skill and fertility of the brain 
must have been well tested to produce the subject before 
them. 

Marine engines may be divided into two classes — beam 
and direct-acting. These may be either condensing or 
non-condensing; the former, however, are the most ex- 
tensively used. With the exception of small screw-pro- 
pellers and tug-boats, and steamers on the Western rivers, 
the condensing or low-pressure engines are almost ex- 
clusively used in this country. What, however, would be 
considered in this country as low-pressure steam, say 40 
pounds to the square inch, would be considered in England 
as high-pressure. 



HAND-BOOK OF LAND AND MARINE ENGINES. 199 




VERTICAL COMPOUND ENGINE. 



200 HAND-BOOK OF LAND AND MAKTNE ENGINES. 

COMPOUND ENGINES. 

The compound engine is a high- and low-pressure 
condensing engine, having two ordinary steam-cylinders, 
the smaller or high-pressure cylinder communicating 
direct with the boiler ; the larger or low-pressure condens- 
ing cylinder direct with the condenser, and both with each 
other. The steam is admitted freely from the boiler into 
the high-pressure cylinder until the piston has been 
moved through a certain distance, when the valve closes, 
and the remainder of the space to be passed through by 
the piston is performed by the expansion of the steam, 
which, after doing its work in the high-pressure cylinder, 
passes into the condensing cylinder, where it does a pro- 
portionate amount of work, and then escapes into the con- 
denser. 

The cyh'nders of an ordinary condensing engine are 
both in connection with the condenser, that is to say, both 
cylinders receive steam direct from the the boiler, and both 
exhaust into the condenser. But with the compound 
engine, one cylinder only receives steam from the boiler ; 
and, instead of exhausting its steam into the condenser, it 
exhausts into a jacket, or into the low-pressure cylinder 
casing. And as the communication to the condenser can 
only be obtained through the low-pressure cylinder, it 
follows that the quantity of steam admitted into the high- 
pressure cylinder does a certain amount of work in it and 
then exhaqsts, and before reaching the condenser does a 
certain amount more of work in the low-pressure cylinder ; 
and as the high-pressure cylinder's exhaust steam enters 
the low-pressure cylinder at a much reduced pressure, the 
low-pressure cylinder is made larger in diameter than the 
high-pressure, for the purpose of equalizing the power, and 
also producing the desired ratio of expansion. 



HAND-BOOK OF LAND AND MARINE ENGINES. 201 

When the length of stroke of both cylinders is the 

same, it has been found, from modern practice, that the 
area of the condensing cylinder should be about three 
times that of the high-pressure one, and this proportion 
is best suited when the steam employed is from 45 to 50 
pounds pressure above the atmosphere, and cutting oif 
the steam after being admitted during l of the stroke in 
the high-pressure cylinder. When the steam to be em- 
ployed is of a less pressure, but the point of cut-oiT the 
same, then the relative proportions of the cylinders must 
be nearer to each other, and the reverse, when steam of a 
greater pressure is to be used. 

The superiority of compound engines over single cylin- 
der engines is due to the fact that the difference of ex- 
treme temperatures in each cylinder is less, and that the 
interior condensation is much diminished ; and also to the 
partial removal of the water from the steam which held 
it in suspension at the time of its leaving the first cylinder, 
so that the water does not pass, in a liquid form, at least, 
to the second cylinder. 

The amount of resisting pressure against the high- 
pressure piston can only be determined by the use of the 
indicator, as it is due in part to the atmosphere, and 
also to the amount of expansion that the steam under- 
goes on being exhausted into the jacket or receiver; 
therefore, the larger the area of the jacket, or receiver, 
the greater is the amount of expansion and consequent 
diminution of pressure, or back pressure, upon the high- 
pressure piston. But this back pressure is of importance 
in a compound engine, as it equalizes the power developed 
by both cylinders, inasmuch as the greater the back 
pressure on the high-pressure piston, the less will be the 
power developed by the high - pressure engine, but the 
greater power will be developed by the low-pressure en- 



202 HAND-BOOK OF LAND AND MARINE ENGINES. 

gine; and shoufd the high - pressure engine exhaust at 
or under the atmospheric line, the greater will be its 
power ; consequently, the less will be the power of the low- 
pressure engine. 

Therefore, in compound engines, the area of the jacket, 
or receiver, should be such as when the high-pressure steam 
is cut off at a certain portion of the stroke and exhausted 
into this jacket, or receiver.' The pressure of steam that 
will enter the low-pressure cylinder shall be such as will 
develop in it equal, or nearly so, power to the high-press- 
ure cylinder. 

As an expansive engine, the compound engine has 
produced very economical results in many instances ; yet 
it is almost too soon to speak with any degree of certainty 
as to its general introduction for marine and stationary 
purposes, as there are questions involved which will re- 
quire several years to determine. Even if compound en- 
gines should be found in all cases capable of producing 
all the economical results claimed for them by their advo- 
cates, they would still labor under the great disadvantages 
of increased first cost, excessive weight, and complication 
of parts. 

The compound engine, both for marine and stationary 
purposes, has had the position of its cylinders and the 
combinations of its parts arranged in mapy different ways, 
in some cases to suit the space available for its erection, 
and in others according to the different ideas of the differ- 
ent manufacturers ; but the principle being the same in 
all cases, an equal economy should be obtained, if care is 
taken in so proportioning the passages for the steam 
that no undue obstruction is caused, and that proper and 
efficient means are employed to prevent any waste of heat. 

The principle of the compound engine was known as 
early as 1781, when Hornblower obtained a patent for em- 



HAND-BOOK OF LAND AND MARINE ENGINES. 203 

ploying steam, after it had acted on one piston, to operate 
on a second by allowing it to expand itself. But Horn- 
blower was never able to practically apply the principle, 
which was successfully carried out by Wolf in 1804. 

DIRECT-ACTING ENGINES. 

Among engineers, generally, the phrase " direct acting " 
is an acknowledged term for the connection of the piston- 
rod with the crank-pin. A "direct-acting'' engine is 
actually a cylinder having within it a piston-fod centrally 
secured, and of the requisite length, proportionate to the 
stroke, with stuffing-box, etc. The introduction of screw 
propulsion created a new exigency in steam mechanics. 
As the propeller was required to make a greater number 
of revolutions than the engines could conveniently per- 
form, therefore it became necessary to couple them directly 
to the propeller shaft, which gave rise to the term " direct 
acting.'' Oscillating and trunk engines have been ar- 
ranged under this title. 

Most of the early forms of this class of engines were 
crude and unsatisfactory, consequently their introduction 
at first had to encounter considerable opposition from 
nautical men; but their excellent performances of late 
years have redeemed them from the disgrace that at one 
time seemed inevitable. They are less bulky and weighty 
than beam or side-lever engines. 

The stroke of direct-acting engines, from want of room, 
is generally very short ; but when it becomes necessary to 
give a direct-acting engine a long stroke, the object is 
effected by inclining the cylinder. Such an engine is then 
termed an inclined engine. 



204 HAND-BOOK OF LAND AND MARINE ENGINES. 




DIRECT-ACTING SCREW-ENGINE. 



HAND-BOOK OF LAND AND MARINE ENGINES. 205 

BALANCING THE MOMENTUM OF DIRECT-ACTING 
ENGINES. 

The application of balance -weights to the cranks of 
direct-acting screw-engines is now a very general practice ; 
and it is found to conduce to the easy and steady working 
of the engines in a very marked manner. 

The principle on which the size of the counter-weights 
should be adjusted to the wants of the engine is of very 
easy apprehension. If the centre of gyration of the coun- 
ter-weights describes a circle of the same radius as that 
described by the crank-pin, then the counter-weights must 
just be as heavy as the piston, and all the parts which 
move with it. 

But if the centre of gyration of the counter-weights 
has a greater radius than the crank -pin, the counter- 
weights must weigh less than the piston and its connec- 
tions, and if it has a less radius, they must weigh more. 
The only material condition being that the momentum, or 
amount of mechanical power resident in the counter- weight 
when moving in one direction, shall balance the momen- 
tum of the piston and its connections when moving in the 
opposite direction, and which weight may be supposed to 
be collected in the crank-pin. 

OSCILLATING ENGINES. 

Oscillating engines are a class of direct-acting engines 
which have no connecting-rod, but in which the piston-rod 
takes direct hold of the crank-pin ; consequently, the cyl- 
inder oscillates or vibrates on trunnions, set near its centre, 
and through which the steam passes and the exhaust 
escapes. These engines have been successfully applied to 
paddle-wheel and even screw propulsion. 
18 



206 HAND-BOOK OF LAND AND MARINE ENGINES. 

The objections formerly raised against their employ- 
ment for marine purposes, namely, that the vibration of 
the cylinder would become a formidable evil in the case 
of a vessel rolling heavily at sea, and that the eduction 
passages being more tortuous than in common engines, 
the steam would escape less freely, and consequently in- 
duce back pressure, and that it would be difficult in large 
oscillating engines to obtain sufficient surface of trunnions 
to prevent them from heating, have proved entirely 
hypothetical, as they have all been successfully overcome 
by a judicious arrangement of the partg. 

It is desirable to make the ends of the cylinders of ordi- 
nary engines as thin, relatively, as is consistent with the 
proper strength of the parts and the provision for- a suit- 
able stuffing-box. But with oscillating engines the case is 
different, as the strains developed by the oscillating mo- 
tion of the heavy cylinder induce a great amount of side 
pressure in alternate directions on the piston-rod, at the 
point where it passes through the cylinder cover. Conse- 
quently, the covers of oscillating cylinders are necessarily 
deeper at their central portions than the like parts of other 
engines. The accurate fitting of this part of an oscillating 
engine is a matter of great importance. 

The piston of an oscillating engine must play tightly 
and easily through the hole in the cylinder-head, while 
provision must also be made for receiving the lateral 
strain due to the oscillation of the cylinder. This is 
effected by lining the aperture for a considerable part 
of its length with brass, and making it in another por- 
tion an ordinary stuffing-box. It is also necessary that 
the piston-rod and crank-pin shaft should have larger 
proportions than those of other engines. The modes of 
attaching, or rather suspending, the cylinders of oscillating 



HAND-BOOK OF LAND AND MARINE ENGINES. 207 

engines differ somewhat. For although a vertical position 
is to be preferred on account of the weight of the cylinder 
appendages, etc. ; yet an angular position is often adopted 
in consequence of being more available for long strokes 
and shallow vessels. 

Oscillating engines have the advantage of simplicity 
of design and fewness of parts, and, in consequence of 
their diminished rubbing surfaces, they require less atten- 
tion and less oil than any other class of engines, and all 
their principal parts are readily accessible should any 
defect be discovered. 

TRUNK-ENGINES. 

The trunk-engine has no piston-rod, but is a direct- 
action engine, in which the connecting-rod takes hold im- 
mediately on the piston itself, through a hollow, open cyl- 
inder within the steam-cylinder. This engine is favorable 
on the score of room, but increases the size and weight 
of the cylinder in order to obtain a given surface of piston 
on which the steam acts. 

With the trunk-engine, the force exerted by the steam 
against the piston is by no means concentrated at once, 
but rather expended at right angles from the face of the 
piston to the crank-pin. This class of engine admits of 
a longer connecting-rod than some other forms of the 
direct-acting engine, and is composed of fewer parts. But 
it is very wasteful of steam, as the large mass of metal of 
the trunk, moving alternately into the atmosphere and 
cylinder, must condense a portion of the steam. The 
trunk also requires a large amount of packing, oil, and 
tallow. 

GEARED ENGINES. 

Geared engines are a class of engines in which, to 
obtain an increased number of revolutions of the pro- 



208 HAND-BOOK OF LAND AND MAKINE ENGINES. 

peller without an increase in the speed of the piston, gear- 
wheels are introduced, by which the motion can be mul- 
tiplied to any required number of revolutions of the screw. 
Formerly, a piston speed to produce 80 or 100 revolutions 
of the screw was considered impracticable, even in short- 
stroke engines, consequently, it was the universal custom 
to obtain it by the intervention of multiplying cog-wheels. 
But with the modern direct-acting engines any desired 
number of revolutions of the screw can be obtained with- 
out the employment of gearing. 

The disadvantagss of geared engines are that they are 
larger, heavier, and occupy more space than direct-acting 
engines ; and, as a result, they fell into disfavor and had 
nearly gone out of use ; but of late years their number 
appear to have increased, as many engineers prefer gearing 
to the high piston speed required in the direct-acting engine. 
The wear on the air-pump is also less with geared engines 
than with direct-acting engines, as its action is more uni- 
form and moderate. 

BACK-ACTION ENGINES. 

The back-action engine is one in which, for economy 
of room and to lengthen the connecting-rod, the cross- 
head and the cylinder are on opposite sides of the shaft. 
This involves the necessity of a double piston-rod to a 
single cross-head, from which a single connecting-rod 
works back on the crank. 

The steeple-engine may be said to be a form of back- 
action engine, with only one piston-rod, strapped to the 
middle of the shortest side of a triangular or harp-shaped 
iron frame, within which the crank revolves, and from 
the apex of which a pair of connecting-rods work back 
on the crank. 



HAND-BOOK OF LAND AND MARINE ENGINES. 209 

SIDE-LEVER ENGINES. 

The side-lever engine is a modification of the beam- 
engine. In river and coast boats the working- beam, or 
lever, is above the engine, and single ; but in the sea- 
going steamers, two of these beams are used instead of one ; 
and instead of being above the engine, they are brought 
down to the bottom, one on each side, and being connected 
by a cross-tail, they act as a single beam or lever. Hence 
is derived the name from the disposition of the working- 
beam, the " side-lever engine." 

So universal has been the use of this engine in past 
years, that, to speak of marine engines, this form of engine 
would be ordinarily understood, unless otherwise specified. 
Although other designs of engines are now of more impor- 
tance to steam navigation, certain it is that no other engine 
in its day was found equal to it in point of efficiency, 
its great drawback being its immense weight and the room 
it occupied. 

BEAM-ENaiNES. 

This class of engines has been very successfully em- 
ployed on coast and river boats, and even ocean steamers, 
and when skilfully managed is capable of attaining a 
very high speed; in fact, when a very high speed is 
desired, the beam-engine is generally employed, as it is a 
well-known fact that all other engines have been distanced 
by their extraordinary performances. 

The objections urged against the employment of the 
beam-engine for marine purposes, namely, its great oscil- 
lation, the resistance due to the wind, exposure in time 
of war, etc., have not been sufficient to counterbalance, or 
ev^n equal, its other good qualities. 

Beam-engines also present great facilities for procuring 
18^ O 



210 HAND-BOOK OF LAJ^fD AND MARINE ENGINES. 




MARINE BEAM-ENGINE. 



A, A. Main frame ; B, B. Keelsons ; C. Cylinder ; D, D. Valve- 
chest ; E. Guides ; F. Beam ; G. Connecting-rod ; I. Valve-stem ; 
K. Condenser; L. Air-pump; M. Boiler feed-pump ; N. Hot- well ; 
O. Delivery -pipe ; R. Link-rod, or main link. 



HAND-BOOK OF LAND AND MARINE ENGINES. 211 

every possible variety of reciprocal motion for pumps of 
less stroke than the piston, as the various feed-pumps, 
bilge-pumps, and air-pumps are very conveniently attached 
to the beam at any point from the centre, outward, and 
each, consequently, is moved with a length of stroke pro- 
portional to such position. 

Beam- and side-lever engines differ from direct-acting 
engines simply in the method of taking the power from 
the piston-rod. In the one, the piston-rod is connected 
directly with the crank ; while in the other, the working- 
beam, vibrating on its centre, receives at one end the power 
from the piston-rod. 

MARINE BEAM-ENGINE. 

The cut on the opposite page represents a marine beam- 
engine. The framework, it will be observed, is com- 
posed of four pieces of wood, which ^re formed into 
two triangles inclined laterally to each other. They are 
fastened together, and to the boat, by numerous horizontal 
and diagonal timbers, which are secured by wooden knees 
and keys. The two front legs of the framing are bolted 
and keyed to diagonal flanges cast on the sides of the con- 
denser. At the other end, the framing is attached to the 
timbers which support the shaft pillow-blocks. The 
framing is further steadied by two additional timbers run- 
ning from the beam pillow-blocks outside the shaft to the 
keelsons. The entire fastening of the engine and fram- 
ing is so arranged as to reduce all the strains to direct 
ones of extension or compression of the fibres of the iron 
and wood employed in the construction. 

The working-beam is composed of a skeleton frame 
of cast-iron, round which a wrought-iron strap of great 
strength is fixed. This strap is forged in one piece, and 



212 HAND-BOOK OF LAND AND MARINE ENGINES. 

its extreme ends are formed into large eyes, which are 
bored out to receive the end-journals. The skeleton frame 
is a single casting in the form of a cross, and contains the 
eyes for the main centre and air-pump journal. 

The bed-plate is a single casting, and forms the foun- 
dation of the heavier portions of the engine. It is care- 
fully fitted upon the keelsons of the boat, and is firmly 
secured by numerous holding-down bolts. That part of 
the plate which lies between the keelsons forms the 
channel- way or passage from the condenser to the air-pump. 
In the centre of this passage are foot-valves. 

The condenser is of a cylindrical form, flanged at both 
ends, and of the same diameter as the steam-cylinder ; its 
contents are about ^gths of that of the space through 
which the piston passes during one stroke. The upper 
extremity is cast close ; the lower end is open, and is fitted 
down to the chipping fillets on the bed-plate, to which it 
is firmly bolted and secured by a rust-joint. On the sides 
of the condenser, and running in an inclined direction, 
strongly bracketed webs or flanges are cast, to which the 
wooden framing that supports the main beam is fastened 
by bolts and keys. 

The cylinder bottom is a circular-flanged casting con- 
taining the lower steam-port. It forms the connection 
between the cylinder and the condenser, to both of which 
it is fitted and bolted. The steam-cylinder is secured to 
its bottom by a rust-joint. It stands vertically over the 
condenser, and has its upper end steadied by horizontal 
stays to the framing. 

The piston is of the ordinary form of spring packing, 
except that, in consequence of its great area, it has to be 
strengthened by radiating arms cast on the top and bottom 
flanges. The cylinder cover is ribbed on the inner side 
similar to the piston-head, its upper or outer surface being 
turned and polished. 



HAND-BOOK OF LAND AND MARINE ENGINES. 213 

The steam-chests contain the valves and seats and the 
inlet and outlet steam passages. On the upper chest is 
cast the throttle-valve pipe, to which is attached the 
supply-pipe leading from the boilers. On the bottom 
chest the exhaust branch is cast, through which the waste 
steam passes to the condenser. The valve-bonnets and 
glands are turned and polished. The chests are ground- 
jointed to the upper and lower steam-ports of the cylinder.' 

The side-pipes, which connect the steam-chests, are of 
cast-iron, ornamented with bands and mouldings, and 
turned and polished throughout their entire length. At 
the upper end of each pipe is an expansion ring of thin 
copper, which, by its yielding, compensates for any slight 
elongation or contraction of the side-pipes occasioned by 
heating and cooking. 

The valves which govern the entrance and exit of the 
steam are connected together in pairs, and of the kind 
called double balance-valves, from the fact that the down- 
ward pressure on one valve is balanced, or nearly so, by 
the upward pressure on the other. The upper valve of 
each pair on the steam-side, and the lower one of each pair 
of the exhaust, are a little larger than the others ; and, 
consequently, there exists a small amount of unbalanced 
pressure, which effectually retains the valves in their seats. 

The valve-gear consists of the lifter-rods with their 
lifters, and the rock-shafts with their levers. There are 
four lifter-rods, which are polished bars of wrought-iron, 
placed in front of the steam-chests. They are made to 
move vertically up and down through guides which are 
cast or bolted to the chests and side-pipes. On the lifter- 
rods are keyed eight projecting arms, called lifters. Four 
of these embrace the extremities of the valve-spindles, 
which are screwed, and provided with double jam-nuts. 
. The remaining four lifters are likewise keyed upon the 



I 



214 HAND-BOOK OF LAND AND MARINE ENGINES. 

rods, and are placed directly over the levers on the rock- 
shafts, from which they receive their motion. There are 
two rock-shafts — one for the steam, and one for the exhaust- 
valves, which are worked by separate eccentrics. On the 
shafts there are four levers, by which the lifters and rods 
are raised, and they are curved on their working faces, in 
order to render their action smooth and noiseless. 

By the reciprocating op rocking motion of the shafts, 
the lifter-rods, and with them the valves, are alternately 
raised and lowered. The exhaust-valve levers are of a 
length just sufficient to give the requisite amount of lift 
and lead, and they are so adjusted on their rock-shaft that 
the moment one rod is fairly down, the raising of the other 
commences. 

The steam-levers are considerably longer, and are 
placed upon their rock-shaft in a position inclined to one 
another, so that an interval, longer or shorter, occurs 
between the falling of one rod and the raising of the 
other. During this interval both valves are down, and 
the steam is, of course, shut off from the piston. This 
arrangement constitutes the expansive cutoff gear, and it 
may be varied by altering the position of the eccentrics on 
the shaft, the levers on the rock-shaft, and the pin in the 
eccentric lever. The amount of lift of the valves may be 
regulated by moving the eccentric-pin. 

The hand rock-shaft, or trip-shaft, is a small shaft of 
wrought-iron working in bearings cast on the lower steam- 
chest. It has solid projections upon it corresponding to 
similar ones on the lifter-rods, and its reciprocating mo- 
tion raises and lowers the valves in precisely the same 
manner as the large rock-shafts. Sockets are formed in 
the trip-shaft, into which the starting-bar is inserted. The 
leverage of this is considerable, whilst the resistance 
amounts to but little more than the weight of the lifter- 



HAND-BOOK OF LAND AND MARINE ENGINES. 215 

rods, valves, and their appendages ; consequently, the 
handh'ng of the engine is performed with great facility. 

STARTING-GEAR FOR MARINE ENGINES. 

The form of starting-gear for marine engines is usually 
a wheel with handles at certain distances on the periphery 
of its rim ; this wheel, being keyed on the end of a shaft, 
having a worm at its opposite extremity, which worm 
gives motion to a toothed segment keyed on a weigh-shaft 
centrally, at each end of which are levers, connected by a 
rod to the slide-valve link. 

Another arrangement of starting-gear is a wheel and 
shaft as above, having keyed on the weigh-shaft a spur-pin- 
ion, which imparts motion to a spur segment ; this motion 
being conveyed to the link as before stated. This last 
arrangement is of a more simple character than the 
former ; but the spur-gear necessitates a friction stop on 
the hand-wheel shaft, to prevent the latter from turning 
during the motion of the engines. 

Perhaps the most modern arrangement is a mitre- 
wheel keyed on the starting-wheel shaft ; the former gears 
with another on the end of a rod, having a coarsely 
pitched screw chased on it ; the screw works in the boss 
of the last mitre-wheel, which revolves on the hand 
wheel giving motion to it, consequently causing the ascent 
or descent of the screw-rod, which is connected to the 
valve-link in the usual manner. In some cases the link- 
rod is connected to a sliding-block, which receives motion 
from the screw ; the rod revolving thus gives motion to 
the link. This latter arrangement is mostly used for 
small engines. 

In the larger class of marine engines, the links are now 
very generally moved by means of a separate engine, to 



216 HAND-BOOK OF LAND AND MARINE ENGINES. 

the cross-head of which they are attached by means of 
rods. 

CONDENSERS. 

In the condensing engine, when the steam is exhausted 
from the cylinder, it escapes to the condenser, where it is, 
as the name implies, condensed into water by being 
brought in contact with a jet of cold water, or by passing 
through a series of tubes, over and around which a stream 
of cold water is continually passing. The former method 
is what is known as "jet condensing,'' while the latter is 
what is termed " surface condensing." 

When the jet condenser is used, salt water must be 
pumped into the boilers, as the water of condensation and 
that of the jet mingle ; but the surface condenser, if per- 
fectly tight, saves the water of condensation, and it can 
be returned to the boilers again and again ; by this means 
nearly all the feed-water is fresh, and but little blowing 
off is required to keep the water at a low point of satura- 
tion. 

The advantages claimed for the surface condenser over 
the jet are, that it furnishes marine boilers with distilled- 
instead of sea- water, which must make a great saving in 
fuel, as it obviates the necessity of continually blowing 
off a portion of the water to keep the saturation at a de- 
sired point, and that it prevents, to a certain extent, the 
loss and danger incurred by the accumulation of salt and 
scale on the heating surfaces of the boilers, and also 
lessens the expense of cleaning and repairing. 

But in practice it has been found that the gain by the 
use of the surface condenser is not nearly so large as 
theory would indicate. Nearly all of them leak to some 
extent, so that salt water mingles with the fresh water 
of condensation. Moreover, all the water that is evapo- 
rated by the boilers is not preserved in the condenser, so 
that salt feed has to be used sometimes. 



HAND-BOOK OF LAND AND MARINE ENGINE^. 217 

Surface condensers are much heavier, more expen- 
sive, and occupy more space than the jet condenser. 
The vacuum also is not so good as that produced by the 
latter. It has also been found that surface condensers in- 
duce corrosion in the boilers; but even with all these dis- 
advantages, it must be admitted that it is a most important 
adjunct of the marine engine. 

The cut on page 218 represents the construction and 
operation of Pirsson's surface condenser. The engine 
being put in motion, the exhaust steam flows through the 
exhaust-pipe, /i, into the chamber, i,i; thence in the direc- 
tion of the arrows through the tubes, returning through 
the lower tubes to the chamber, k; injection water being 
admitted at the same time from the sea through the injec- 
tion-pipe, r, is showered by the scattering-plate, s, over the 
tubes, and by its gravity takes the direction of the arrows 
to the channel-way, t, from which it is removed by the air- 
pump, V, and delivered into the hot-well, w, to the delivery- 
pipe, Xf and thence overboard. 

The water resulting from condensation is drawn by the 
fresh-water pump, m, from the chamber, k, through the pipe, 
/, I, and delivered into the fresh- water reservoir, n ; from 
this reservoir it passes through the pipe, o, to the feed- 
pump, P, and is delivered into the boilers through the feed- 
pipe, g. The pipe, y, is for the purpose of supplying salt 
Avater to the feed-pump, P, when there is a deficiency of 
fresh water in the reservoir, n. 

In some forms of condensers, the operation is the re- 
verse of the one just described, as the exhaust steam is re- 
ceived on the outside of the tubes, and is condensed by 
water circulating through them. 

The quantity of injection water and water of conden- 
sation is about the same with both surface and jet con- 
densers. Therefore, the work performed by the single air- 
19 



218 HAND-BOOK OR ^AND AND MARINE ENGINES. 




PIRSSON'S SURFACE CONDENSER. 
EXPLANATION. — G, G, condenser ; hy exhaust-pipe ; i, % exhaust- 
chamber ; k, exhaust-passage; I, I, fresh-water pipe; r, injection- 
pipe; 5, scattering-plate ; ^, injection channel; i;, air-pump ; w, hot- 
well ; X, delivery -pipe ; m, fresh-water pump ; n, fresh-water reservoir ; 
o, fresh-water supply-pipe ; P, feed-pump ; q, feed-pipe ; y, salt-water 
supply-pipe. 



HAND-BOOK OF LAND AND MARINE ENGINES. 219 

pump of the latter is the same as that performed by the 
two air-pumps of the former. The temperature of the 
feed-water, in both cases, ranges from 100° to 110°; so 
that it is obvious that the gain with the surface condenser 
is reduced to that due to not blowing out, and to the 
cleaner condition of the boilers, as stated in a former 
paragraph. 

When the engine is standing still, it frequently hap- 
pens that, in consequence of leaky steam- and exhaust- 
valves, the condenser becomes too hot ; consequently, when 
it is necessary to start, the pressure is so great in the con- 
denser that the injection water will not enter. Overheat- 
ing of the condenser is always indicated by a cracking 
noise. In such cases, it is always best to pump some cold 
water into the condenser, if there be any independent 
arrangement for that purpose; if not, the temperature can 
be lowered by pouring cold water over the outside of it, 
or the pressure can be lessened by moving the engine back 
and forth two or three revolutions. 

Relative Quantities of Injection and Condensed Wa- 
ter.— -The injection water enters the condenser at a certain 
temperature, and, coming in contact with the steam, its 
temperature is increased and that of the steam dimin- 
ished, all the latent heat of the steam being made sensible. 
It only becomes necessary to ascertain the quantity of 
water that will absorb the heat contained in the steam. 

Suppose the temperature of the steam entering the con- 
denser to be 1188°, and that of the injection water 60°, 
while the discharge water is 110°. Now, as the water of 
condensation has a temperature of 110°, there are*1188° — 
110° = 1078° imparted to the injection water. But a 
quantity of injection water equal to the water of conden- 
sation receives 110°— 60°= 50°. Hence the quantity that 
receives 1078° of heat will be 1078° -r- 50°= 21*56 times 



220 HAND-BOOK OF LAND AND MARINE ENGINES. 

the water of condensation ; or, in other words, the injection 
water is necessarily from twenty-one to twenty-two times 
greater than the water of condensation. 




Seweli's Surface Condenser. 

The above cut represents SewelFs surface condenser. 
The air-pump, D, is double-acting, and has two sets of foot- 
and delivery-valves — one set being for the injection, and 
the other for the water of condensation. The injection 
water enters at the opening, L ; is drawn through the foot- 
valves, M, N, O, and forced through the delivery-valves, P, 
through the tubes, T, and overboard through the overboard 
delivery, W. The exhaust steam enters at E, and is con- 
densed by contact with the outer surfaces of the tubes. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



221 



The water of condensation is drawn through the foot- 
valves, F G H, and is forced through the delivery-valves, 
I, and the outboard, K, into a reservoir, from which the 
feed-pumps draw their water. 

There is a loaded valve in this reservoir, communicating 
with the outboard delivery, so that, when the reservoir 
becomes full, the water may escape. The openings, V U, 
are the ends of a pipe connecting the fresh- and salt-water 
reservoirs, so that any deficiency in the feed- water may be 
supplied from the latter reservoir. R is an air-chamber 
for the salt-water reservoir, and S is the end of a pipe 
through which the auxiliary pump draws water. 

The tubes in this condenser are not secured to the 
tube-heads, but pass through them, and are made tight by 
rubber grummets. By this means each tube is allowed to 
expand and, contract independently of all the others. 

The following cut represents a jet condenser. 




Jet Condenser. 

O, Exhaust-pipe ; P, injection-pipe ; Q, jet ; K, foot-valve ; 
vS, air-pump cylinder; U, U, air-pump valves; V, air-pump rod ; 
W, deli very- valve ; T, hot-well. 
19* 



222 HAND-BOOK OF LAND AND MARINE ENGINES. 

AIR-PUMPS. 

All condensing engines have, of necessity, to be sup- 
plied with an air-pump, the chief function of which is to 
remove the injection water, or water of condensation, and 
extract the air that has been liberated from the water in 
boiling, from the condenser. 

The proper proportions of the air-pump were deter- 
mined by Watt to be about one-eighth, of the capacity of 
the cylinder. In more modern engines, especially where 
there are irregularities of motion, the air-pump is gener- 
ally made- a little larger than this proportion. 

The capacity of the air-pump depends on the quantity 
of water injected, and this again depends on the quantity 
of steam to be condensed. If the steam is worked expan- 
sively, the pump may be smaller than if it was worked 
whole-stroke. And if it be double-acting, it ne^d only be 
half as large as if single-acting. 

If the condenser be considered as a well from which 
the water is to be pumped, we notice a manifest difference 
between the duty of the air-pumps and that of other 
pumps, inasmuch as the condenser is not open to the air, 
and the ascent of the water cannot be assisted by the 
pressure of the atmosphere. The bucket, therefore, cannot 
be raised to any great height above the condenser with 
the expectation that the water will follow the bucket on 
its up-stroke. 

In quick-working engines, the shock on the delivery- 
valve, on the ascent of the bucket of the air-pump, is con- 
siderable, and produces a very disagreeable noise. To 
prevent this, a small valve is sometimes fitted, to admit 
air above the bucket as it descends.. 

The air-pump is generally attached to the sole-plate by 
a faucet-joint, which is preferable to a rust flange-joint, 
as the salt water eats away the heads of the bolts, unless 



HAND-BOOK OF LAND AND MARINE ENGINES. 223 

they are copper ; and if they are copper, they waste the 
iron. The oil and grease which fall from the machinery 
upon the sole-plate deoxidize the rust of a flange-joint ; 
whereas with a faucet-joint, suitably made, they cannot 
remain in the same intimate contact. Air-pump barrels, 
buckets, and valves are almost entirely made of brass or 
Muntz's metal ; the rods are generally made of iron and 
covered with a skin of brass; the valves are most com- 
monly of the spindle or pot-lead kind. 

The most common methods for working air-pumps are 
either by a rod from the main beam, or by the oscillation 
of the cylinder or a crank or large eccentric on the main 
shaft ; although air-pumps are in some cases worked inde- 
pendently by means of a separate engine, 

THE HYDROMETER, SALINOMETER, OR SALT-GAUGE, 

Ocean steamers, using sea-water in the boilers, require 
frequent change of the water to prevent incrustation, or 
deposit of salt and earthy matter upon the flues 
and within the legs- of the boilers. This exchange 
should be made with regularity and care, lest, 
on one hand, the object sought should not be at- 
tained, or, on the other, a waste of heat should 
be occasioned in discharging hot water too freely 
from the boiler, the place of which is to be sup- 
plied with cold. 

It is, however, better, as a general thing, to 
err on the side of a too liberal use of the blow- 
off* cock ; for the loss of heat would probably be 
less from this cause than it would be if the 
boiler were allowed to become incrusted with a 
non-conducting substance. At what exact degree of 
saturation saline incrustation begins has not as yet been 




224 



HAND-BOOK OF LAND AND MARINE ENGINES. 



determined, but it appears to vary considerably under 
different circumstances ; consequently, the wisest course to 
pursue would be to be governed by practice rather than 
by theory. 

It is necessary, therefore, to have some test by which 
the saltness of the water may be known, and, having this, 
to adopt such a system of blowing-off as will keep the 
water uniformly at the degree fixed upon. The degree 
of saltness is ascertained by the hydrometer. It is gradu- 
ated to show the number of ounces of salt contained in 1 
U. S. gallon (8*338 avoirdupois pounds), and can be made 
of either glass or metal. 

Sea-water is generally understood to contain 3^3, by 
weight, of salt ; but this proportion varies in the water of 
diflerent seas, as will be seen in the following table : 



Parts in 1000. 

Baltic Sea, 6*60 = j^ 2 

Black Sea, 21*60= :fV 

Arctic Sea, ..28-30= 3V 

Irish Sea, 33-76= ^V 

British Channel,35-50 = -}^ 



Parts in 1000. 

Mediterranean Sea, 39*40 = 2V 

Atlantic at the Equator,... 39*42 = 2? 

South Atlantic, .41-20 = ^\ 

North Atlantic, 42-60=27 

Dead Sea, 385-00 = ^ 



The boileps of ocean steamers are usually filled with 

fresh water before starting on their voyages, and, as they 

are generally fitted with " surface condensers," they use 

no saltwater at all, the loss of fresh water induced by 

leakage, etc., being replaced by water distilled by an 

apparatus with which nearly every ocean steamer is 

supplied. 

THE MANOMETER. 

The Manometer, according to the derivation of the 
word (from manos, rare, and metron, measure), is an in- 
strument for measuring the degree of rarefaction j^ aeri- 
form fluids subjected to less than atmospheric pressure. 



HAND-BOOK OF LAND AND MARINE ENGINES. 225 

The term is also, and more generally, applied to the 
instrument when used to indicate the density of aeriform 
fluids subjected to more than atmospheric pressure. The 
manometer may therefore be defined to be an instrument 
for measuring the density of aeriform fluids by means of 
a glass tube inserted in a reservoir of mercury. At the 
ordinary pressure of the atmosphere, the mercury will 
stand about 29^ or 30^ above the level of the mercury in 
the reservoir; but as soon as the pressure above the sur- 
face of the mercury in the reservoir becomes less than 
that of the atmosphere, the column of mercury will, of 
course, fall in the tube just in proportion to the diminution 
of the pressure. 

THE BAROMETER. 

The Barometep is an instrument used for observing the 
pressure and elasticity, or variations in density, of the 
atmosphere. It is commonly employed for the purpose 
of determining approaching variations in the w^eather, and, 
more scientifically, for measuring altitudes. There are 
various modifications of the barometer, such as the diago- 
nal, horizontal, marine, pendant reduced, and wheel 
barometer ; in all of which the principle is the same, the 
only difference being in its application. The essential part 
of a barometer is a well-formed glass tube, closed at one 
end, perfectly clear and free from flaws, 33 or 34 inches 
long, of equal bore, filled with pure mercury, and inverted ; 
the open end being inserted in a cup partly filled with the 
same metal, so that the mercury in the tube may be sup- 
ported by atmospheric pressure. 

The excellence of the Barometer depends chiefly on 
the absence of all matter except mercury from the tube, 
and its value may be tested by three indications : — First^ 
by the brightness of the mercurial column, and the ab- 

P 



226 



HAND-BOOK OF LAND AND MARINE ENGINES. 



sence of any flaw, speck, or dulness of surface ; secondly, 
by the " barometric light," as it is called, or flashes of 
electric light in the Torricellian vacuum, produced by the 
friction of the mercury against the glass when the column 
is made to oscillate through an inch or two in the dark ; 
thirdly, by a peculiar clicking sound produced when the 
mercury is made to strike the top of the tube. If air be 
present in the tube, it will form a cushion at the top, and 
prevent or greatly modify this click. 

The vacant space between the top of the mercury and 
the top of the tube is called the Torricellian vacuum, in 
honor of the inventor of the instrument. 



MARINE ENGINE REGISTER, CLOCK, AND VACUUM 
GAUGES. 

The annexed cut represents a marine engine register or 
counter, clock, and steam- and vacuum-gauges. It con- 




Marine Engine Register, with Clock, Steam-gauge and Vacuum-gauge, 



HAND-BOOK OF LAND AND MARINE ENGINES. 227 

sists of a circular cast-iron box, in which are cut, side by 
side, six (or more as may be required) slots, through 
which may be seen the numbers representing the revolu- 
tions of the engine ; this is denominated the " counter " or 
register. By an attachment to any suitable part of the 
engine, a vibratory motion is communicated to an arm 
attached to a central horizontal shaft, placed parallel to 
the dial, and within the cast-iron box ; to the ends of 
which is also fixed a frame carrying a small shaft parallel 
to the former, on which six palls, or arms, are attached, side 
by side, and at a certain distance apart, in such a way 
that the right-hand pall may fall without the others, but 
cannot rise without carrying all the rest. 

This framework, with the pall-shaft, etc., is made, by 
the motion of the arm attached to the engine, to describe 
an arc of 36°, or to move through y^ of a circle. The 
ends of the palls respectively rest on and slide over six 
cylinders, placed side by side on the central shaft, all of 
which are free to move in the same direction and inde- 
pendently of each other, and are arranged as 1, 2, 3, 4, 
etc., beginning with the right-hand one. 

On the right-hand edge of each cylinder are cut ten 
slots, and on the left-hand, which overlaps the edge of the 
next, only one slot — these slots being of such a size as will 
admit of one of the palls ; then, on the back motion of 
the framework, etc., the pall is carried back till it drops 
in, when the forward motion carries with it the cylinder 
so locked. 

STEAM-GAU&ES. 

The use of the steam-gauge is to indicate the steam 
pressure in the boiler, in order that it may not be increased 
far above that at which the boiler was originally consid- 



228 



HAND-BOOK OF LAND AND MARINE ENGINES. 




Steam-gauge. 



ered safe; and it is as a provision against this contingency 
that a really good gauge is a necessity 
where steam is employed, for no guide 
at all is vastly better than a false one. 
The most essential requisites of a good 
steam-gauge are, that it be accurately 
graduated, and that the material and 
workmanship be such that no sensible 
deterioration shall take place in the 
course of its ordinary use. 

The pecuniary loss arising from 
any considerable fluctuation of the 
pressure of steam has never been 
properly considered by the propri- 
etors of engines. If steam be carried 
too high, the surplus will escape 
through the safety-valve, and all the fuel consumed to 
produce such excess is so much dead loss. On the other 
hand, if there be at any time too little steam, the engine 
will run too slow,- and every lathe, loom, or other machine 
driven by it, will lose its speed just exactly in the same 
proportion, and of course its effective power. 

A loss of one revolution in ten at once reduces the 
productive power of every machine driven by the engine 
ten per cent., and loses to the proprietor ten per cent, of 
the time of every workman employed to manage such 
machine. In short, the loss of one revolution in ten di- 
minishes the productive capacity of the whole concern ten 
per cent, so long as such reduced rate continues ; while 
the expenses of conducting the shop (rent, wages, insur- 
ance, etc.) all run on the same, as if everything was in 
full motion. A variation to this amount is a matter of 
frequent occurrence, and is, indeed, unavoidable, without 
proper instruments to enable the engineer to avoid it. 



HAND-BOOK OF LAND AND MARINE ENGINES. 229 

A very little reflection will satisfy any one that it must 
be a very small concern, indeed, in which a -half-hour's 
continuance of it would not produce a result more than 
enough to defray the cost of a very expensive instrument 
to prevent it. If the engineer, to avoid this loss, keeps a 
surplus of steam constantly on hand, he is then constantly 
wasting the steam, and consequently fuel, and thus incurs 
another loss, which, though less alarming than the first, 
will yet be a serious one, and render any instrument most 
desirable which can prevent it. 

It is evidently, therefore, of great importance to the 
proprietors of engines to have an instrument which should 
constantly indicate the pressure in the steam-boilers. This 
would enable the engineer to keep his steam at a constant 
pressure, and thus avoid waste of fuel, on the one hand, 
and the still more serious loss of the productive power of 
the shop, on the other. An instrument, therefore, con- 
stantly indicating the pressure of steam, reliable in its 
character, and, with ordinary care, not subject to derange- 
ment, is evidently a desideratum both to the engineer and 
proprietor. The importance of such an instrument, as a 
preventive of explosion, and of the frightful consequences 
to life and limb, and ruinous pecuniary results of such 
disaster, is obvious on the slightest consideration ; but the 
value of the instrument, in the economical results of its 
daily use, is by no means properly appreciated. 

Steam-gauges are made in various forms, but they may 
be divided into two general classes — spring and mercury. 
The spring-gauge, in consequence of being cheaper, more 
compact and durable, and frequently more ornamental 
than the mercury-gauge, is more generally used on sta- 
tionary and locomotive boilers ; but it is less reliable than 
the latter — reliability being the great desideratum in a 
steam-gauge. 
20 



230 



HAND-BOOK OF LAND AND MARINE ENGINES, 



The Spring-gauge. — The principle of its construction is 
as follows : When a thin metallic tube is nearly flattened 
and afterwards coiled, the effect of any inward pressure is 
to force it towards its original shape, — the first effect pro- 
duced being that of tension towards elongation, whether the 
flattened tube be coiled or twisted ; and a contrary effect 
is produced by unresisted exterior pressure. 

In shaping it, a certain degree of elasticity having been 
given to the metal, as long as it is not absolutely forced 
beyond a given point of its acquired shape, it will act as 
a spring to the greatest perfection, and work from or back 
to its newly acquired shape, as the pressure upon it may 
be applied. 

Thus, a simple piece of well-made metal tube is first 
partially flattened in all its length, and coiled nearly to a 
circle. One end of it is stopped up, while the other is left 
open, to receive the pressure of steam or water. To the 
end that is stopped up a hand is fixed, 
which is so placed as to show the va- 
riations in the position of the tube 
upon a dial marking the degrees of 
pressure. 

The spring-gauge can also be used 
as a vacuum-gauge, by reversing the 
application of the pressure, which has 
a contrary effect on the tube. For 
instance, as exhaustion takes place in 
the tube, so does its power of resist- 
ing the pressure of the surrounding 
atmosphere which acts upon it vary, 
and it consequently again coils under 
Vacuum-gauge. ^j^^^ pressure in regular ratio with the 
variation of it, and is made to indicate the degree of 
vacuum in the condenser of an engine. 




HAND-BOOK OF LAND AND MARINE ENGINES. 



231 



The Mepcupy-gauge. — The mercury-gauge is the surest 
and simplest of all gauges, but is often inconvenient on 
account of the space it requires. When used for station- 
ary boilers, it consists of a vertical glass tube communi- 
cating with a cistern of mercury, which rests on a steel or 
gutta-percha disk ; its chief drawback for stationary pur- 
poses is its first cost, which is about twice that of the 
spring-gauge. It is not adapted to locomotive boilers. 

When used fop mapine pupposes, it consists of a siphon 
tube partially filled with mercury, one end of which is 
subjected to the pressure of the steam, whilst the other is 
open to the air. The pressure tends to displace the column 
in one leg and raise it in the other ; the diflerence between 
the two shows the amount of pressure. 

An invepted siphon filled with mercury, 
with a rod floating on its surface, was 
among the earliest inventions of the fathers 
of the steam-engine ; and for steam of one 
or two atmospheres, this is still the most 
reliable of the appliances in use at the 
present day ; but for steam of higher press- 
ure, they become less reliable and conve- <(^Z^ 
nient, in consequence of their great height, 
the friction of the float, and their liability 
to lose the mercury by its oscillation or by 
excess of pressure. 

The mepcupy, when not pressed upon 
by steam, will stand at a level in both legs 
of the siphon ; and even when an atmosphere i i j 

of steam has taken the place of the atmos- V^llx 

pheric air in the boiler, the mercury will Siphon-gauge. 
still stand at the same level. But when the 
pressure increases, it will press with greater force on the 
mercury in the leg exposed to the pressure of the steam 



232 HAND-BOOK OF LAND AND MARINE ENGINES. 

than the atmosphere presses on the mercury in the leg 
open to the air ; consequently, the mercury will rise in the 
open leg, and indicate the excess of pressure of the steam 
beyond that of the external air. 

The graduations on the mercurial gauge are an inch in 
length. Every inch that the mercury rises in the gauge 
indicates an alteration of two inches in the level of the 
column supported in the bent tube ; consequently, one 
inch of mercury on the scale indicates a pound pressure 
of steam. 

A coiumn of atmosphere 45 miles high, and one square 
inch in area, just balances, and consequently weighs the 
same as a column of mercury of like area and 30 inches 
high. This column of air also balances 33| feet of water. 
Consequently, a column of air 45 miles high, 30 inches of 
mercury, and 33| feet of water, weigh the same. 

1 atmosphere, or 15 POunds 1 g^ j^^j^^^ ^^ ^^^^^^^ 

per square inch, 3 

Each pound pressure | _ ^ .^^^^^ ^^ ^^^^^^^^ 

per square inch ) 
Each pound pre^ure ) _ ^ .^^^^ ^j^^ ^^ siphon-gauge. 

per square inch j 
1 atmosphere, 15 pounds | ^ 33, ^^^ ^^ ^^^^^ 

per square inch, 3 

Each pound pressure J _ ^^ .^^^^^ ^^ ^^^^^ ^^^^1^ 

per square inch 3 

Suppose it were possible to erect a tube having a 
sectional area of one square inch upon any part of the 
earth, and that this tube be long enough to reach up to the 
height of the atmosphere (which is supposed to be about 
45 miles), the air contained in such a tube would weigh 
about 14| pounds. Now, if we take another tube, having 



HAND-BOOK OF LAND AND MARINE ENGINES. 



233 



the same sectional area, and place 14f pounds of water in 
it, the level of the water will be found to be 33i feet 
above the bottom of the tube. If we take still another 
tube of the same area, and place 14} pounds of mercury 
in it, the level of the mercury will stand 30 inches above 
its base. 

GLASS WATER-GAUGES. 

The glass water-gauge may be said to be one of the 
simplest, as well as one of the most useful, attachments of 
the steam-boiler, as by it the engineer can 
see at a glance the level of the water. No 
other method of determining the height of 
water in steam-boilers can be so reliable 
as a well-made glass water-gauge. Conse- 
quently, they have been almost universally 
used since their introduction to the present 
time. 

It consists of a thick, well-annealed glass 
tube connected with two valves, the lower 
one of which enters the wiiter, and the 
upper the steam space of the boiler, by 
means of which the level of the water is indicated directly 
in the tube. These valves can be opened or shut so that 
the tube may be filled with either water or steam, or both, 
or b^ blown out. The tube is packed on each end with 
thin rubber collars, which are made steam- and water- 
tight by means of stuffing-boxes. 

A very important improvement has been recently made 
in glass water-gauges by M. Pennypacker, Supt. of the 
Baldwin Locomotive Works, Phila., by which the 
dangers heretofore incurred by the breaking of the glass 
tubes, in the absence of the engineer, is entirely obviated, 
as, in case the glass should become broken, the steam and 
20* 




234 HAND-BOOK OF LAND AND MARINE ENGINES. 

water communications with the boiler are instantly auto- 
matically closed by means of balanced valves. 

As long as the glass tube is unbroken, the valves are 
nearly balanced, and will remain open, owing to their own 
weight ; but should the glass tube break, the pressure on 
the top of the valves being removed, the pressure under 
them will instantly force them to their seats, thereby 
effectually shutting off the water and steam from the 
broken tube. This gauge is also so arranged that the 
steam and water may be shut off from the boiler in the 
usual manner, should the self-acting valves fail to close, 
as the position of the positive stop-valves, is placed 
between the self-acting valves and the boiler, which also 
allows the latter to be taken out and cleaned with the full 
pressure of steam on the boiler. These gauges will prove 
invaluable to steam-users, who are of necessity compelled 
to locate their boilers in the midst of valuable property. 

Glass gauges require frequent blowing out, as the tube 
soon becomes discolored, and the lower or water connection 
is liable to become filled with mud. This can be done by 
opening the drip at the bottbm of the gauge and closing 
the water-valve, when the steam will rush down through 
the tube and remove any deposit that may be on the in- 
side of the glass.- 

Should it become necessary to use a swab, it must, in all 
cases, be of wood and covered with cloth, as the toucji of 
any hard substance on the inside of the glass produces an 
immediate abrasion. If the end of the swab be dipped in 
acetic acid, it has the effect of removing all discoloration 
from the inside of the tube. 

Magnetic water-gauges are sometimes used on stationary 
and marine boilers. This kind of gauge consists of a 
movable magnet inside of the boiler, which controls a 
needle on a dial on the outside, the connection between 
the two being entirely magnetic. 



HAND-BOOK OF LAND AND MARINE ENGINES. 235 




Richards' Indicator. 

THE STEAM-ENGINE INDICATOR. 

The steam-engine indicator is an instrument designed 
to show the pressure of steam in the cylinder at each 
point of the piston's stroke. It does this in the following 



236 HAND-BOOK OF LAND AND MARINE ENGINES. 

manner : A pencil, moving up and down with- the varying 
pressure of the steam, draws a line on p^per, which has a 
motion backward and forward coincident with that of 
the piston. 

The paper is placed on a drum, which, while the pis- 
ton is advancing, is caused to make about three-quarters 
of a revolution by means of a cord connected with a suit- 
able part of the engine, and, while the piston is receding, 
is brought back to its first position by the reaction of a 
spring. The pencil is attached to a small piston moving 
without friction in a cylinder, and the motion of which is 
resisted by a spring of known elastic force. 

The pressure of the atmosphere is always on the upper 
side of this piston, and when the communication with the 
cylinder of the engine is closed, it is on the under side 
also ; and if then the motionless pencil be applied to the 
moving paper, it will draw a line which is called the 
atmospheric line. 

When the communication is opened between the under 
side of this piston and one end of the cylinder of the en- 
gine, the piston will be forced upward by the pressure of 
the steam, or downward by that of the atmosphere, as the 
one or the other preponderates. And if now the pencil be 
applied to the moving paper, it will describe, during one 
revolution of the engine, a figure, each point in the outline 
of which will show, by its distance above or below the 
atmospheric line, the pressure in that end of the cylinder, 
when the piston was at the corresponding point of its 
forward or return stroke. 

The spring which resists the motion of the indicator- 
piston is so proportioned in strength that a change of press- 
ure of one pound on the square inch will cause the 
pencil to move up or down a certain fractional part of an 
inch. 



HAND-BOOK OF LAND AND MARINE ENGINES. 237 

The diagram thus described shows on inspection the 
following particulars, viz. : what proportion of the boiler 
pressure is obtained in the cylinder; how early in the 
stroke the highest pressure is reached ; how well it is 
maintained; at what point and at what pressure the 
steam is. cut off; whether it is cut off sharply, or in what 
degree it is wire-drawn ; at what point and at what press- 
ure it is released ; in a non-condensing engine, whether it 
is freely discharged, or what proportion of it remains to 
exert a counter-pressure ; in a condensing engine, the 
amount of the vacuilm, and how quickly or how gradually 
it is obtained ; and, in both classes of engines, whether, 
before the commencement of the stroke, there is any com- 
pression of the vapor remaining in the cylinder, and if so, 
at what, point it commences, and to how high a pressure 
it rises. 

From the diagram, the mean pressure exerted during 
the stroke, to produce and to resist the motion of the pis- 
ton, may be ascertained, and thus the engineer may come 
to know accurately the amount of power required to 
overcome the whole aggregate resistance on the engine. 

It must be borne in mind that the indicator shows only 
the pressure at each point of the stroke ; to represent this 
faithfully is its sole ofBce. It tells nothing about the 
causes which have determined the form of the figure which 
it describes. The engineer concludes what these are as 
the result of a process of reasoning, and this is the point 
where errors are liable to be committed. 

Conclusions which seem obvious sometimes turn out to 
be wrong, and the ability to form an accurate judgment as 
to the causes of the peculiarities presented in a diagram, 
is one of the highest attainments of an engineer. 

The variety of diagrams given by different engines, 
and by the same engine under different circumstances, is 



238 



HAND-BOOK OF LAND AND MARINE ENGINES. 




endless ; and there is perhaps nothing more instructive to 
the student, or interesting to the accomplished engineer, 
than their careful and comprehensive study, with a knowl- 
edge of the varying circumstances under which each one 
was taken, as the lines, at first meaningless, become full of 



HAND-BOOK OF LAND AND MARINE ENGINES. 239 

meaning— -that which scarcely arrested his attention comes 
to possess an absorbing interest. He becomes acquainted 
with the innumerable variety of vicious forms, and learns 
the points and degrees, as well as the causes, of their de- 
parture from the single perfect form. 

He also becomes familiar with the effects produced by 
different constructions and movements of parts, and com- 
petent to judge correctly as to the performance of engines, 
and to advise concerning changes, by which it may be 
improved. He ceases to be a mere imitator of material 
shapes, and learns to strive after the highest excellence, 
and at the same time to comprehend its conditions. 

No one at the present day can claim to be a mechani- 
cal engineer who has not become familiar with the use of 
the indicator, and skilful in turning to practical advan- 
tage the varied information which it furnishes. 

In order to know the condition of the internal working 
parts of an engine from a diagram taken from it, it is 
necessary to make a perfect diagram around it, so as to 
compare one with the other. 

It is of the first importance, of course, that the diagram 
given by the indicator shall be true. Causes of error appear 
at every point, and the degree of falsity arising from them 
increases greatly with an increase in the rate of revolu- 
tion of the engine. It is not possible to be too critical in 
using the indicator, especially at high speeds ; the errors 
we are not conscious of are the ones sure to mislead us. 

Conditions to be observed in order to obtain a correct 
Diagram. — Be sure that the movements of the paper 
shall coincide exactly with those of the piston, and that 
the movements of the pencil shall simultaneously and 
precisely represent the changes of pressure in that end of 
the cylinder to which the indicator is attached. 



240 HAND-BOOK OF LAND AND MARINE ENGINES. 
Diagram No. 2. 



— -— ^-Ajre a77i StroKe-^-—————-^^ — . 




Diagram No. 2 is a theoretic diagram. 
Diagram No. 3. 



Expansion 
Corner 



: ^ — — ^^^«: Starting 

SteamStroke Cortipr \ 



I 




Eduction 

Corner- 



L c ad 



~VaCZLZL7}l Li 



Diagram No. 3 is divided into as many parts as there are inches in 
the stroke of the piston. The perpendicular lines indicate the corre- 
sponding pressure ; the curved line, a7>, shows the varying pressure 
of the steam. 



HAND-BOOK OF LAND AND MAKINE ENGINES. 241 

The common errops in communicating motion to the 
paper are of two kinds, — those which arise out oF the 
movements employed, and those which, when the move- 
ments are correct, are occasioned by a high velocity of the 
parts ; but with pro|)er care these may all be avoided. 

Errors in the motion of the pencil are of a more serious 
nature. The spring may be accurate, but its unavoidable 
length and weakness, and its weight, joined to that of the 
piston and other attached parts, and the distance through 
which these must move, in order that the indications may 
be on a scale of sufficient magnijtude, render it almost im- 
possible to obtain, from engines which run at a high speed, 
correct diagrams. 

METHOD OF APPLYING THE INDICATOR. 

When it is practicable, diagrams should be taken from 
each end of the cylinder. The assumption made, that 
if the valves are set equal, the diagram from one end will 
be like that from the other, will be shown by this instru- 
ment to be erroneous, as It often occurs that there is a dif- 
ference in the length of the steam passages, and in the 
lead, or the amount of opening, or the point of closing. 
These, and many other causes, will make a difference in the 
diagrams obtained from the opposite sides of the piston. 

The indicator sliould be fixed close to the cylinder, 
especially on engines working at high speeds ; and if pipes 
must be used, they should not be smaller than half an inch 
in diameter. 

On vertical cylinders, for the upper end, the indicator- 
cock is usually screwed into the head, where the oil-cup 
is set, it being removed for the purpose. For the lower 
end, it is necessary to drill into the side of the cylinder at 
a convenient point in the space between the cylinder-head 
21 Q 



242 HAND-BOOK OF LAND AND MARINE ENGINES. 

and the piston, when the crank is at the centre, and screw in 
a short bent pipe, with a socket on the end to receive the 
indicator-cock. 

Fop horizontal cylinders, the best place for the indi- 
cator is on the top or upper side, at each end ; if it cannot 
be placed there, bent pipes may be screwed into the heads 
or into the side of the cylinder. The indicator should 
never be set to communicate with the port passages, as the 
current of steam passing the end of the pipes has a ten- 
dency to reduce the pressure in the instrument. 

On oscillating cylinders, care must be taken to set the 
instrument in such a position that the motion of the cyl- 
inder will not have the effect to throw the pencil to and 
from the paper. 

Proper Points from which to derive the Motion. — This 
may be taken from any part of the engine which has a 
motion coincident with that of the piston. For a beam- 
engine, a point on the beam, or beam-centre, will give the 
proper motion ; but care must be taken that the cord be 
so led off that, when the engine is on the half-stroke, it 
will be at right angles to whatever gives it motion. For 
horizontal and vertical engines, the motion of the paper 
is generally taken from the cross-head. For oscillating 
engines, the motion may be taken from the brasses at the 
end of the piston-rod. 

Facts to be recorded when Diagrams are taken. — 
The form of engine, whether single or double. Length 
of stroke, diameter 0/ cylinder, and number of strokes 
per minute. 

The size of the ports, the kind of valve employed, the 
lap and lead of the valve, and the exhaust-lead. 

The amount of the waste-room, in clearance and pass- 
ages. The pressure of steam in the boiler, the diameter 
and length of the steam-pipe, and the point of cut-off. 



HAND-BOOK OF LAND AND MAEINE ENGINES. 243 

^^'Fop locomotives, the diameter of the driving-wheels, 
aiid the size of the exhaust-nozzle, the weight of the train, 
and the gradient, or curve. 

Fop condensing engines, the vacuum by the gauge, the 
kind of condenser employed, the quantity of water used 
for one stroke of the engine, its temperature and that of 
the discharge, the size of the air-pump and length of its 
stroke, whether single- or double-acting ; and, if driven in- 
dependently of the engine, the number of its strokes per 
minute, and the height of the barometer. 

The description of boiler used, the temperature of the 
feed-water, the consumption of fuel and of water per hour, 
and whether the boilers, pipes, and engine are protected 
from loss by radiation, and if so, to what extent. 

Obsepvations on the Chapactep of the Diagpam, — If 
the expansion corner is much cut away, the engine is' 
working to a proportionate extent expansively. 

If the eduction corners are much cut away or slanted, 
the exhaust-passages are too small. 

If the lead corner is much slanted off, then the lead 
given to the engine is great ; the steam side of the valve is 
opened before the end of the stroke, or the exhaust-passage 
is shut too soon, which causes compression. 

In some cases the vapor may be compressed beyond the 
pressure of the steam, and cause the line of the diagram ' 
to form a loop above tjie steam line at the starting corner. 

If the starting corner is slanted much, then the steam is 
not admitted sufficiently early. 

Every change in the engine which diminishes the area 
of the diagram, by the rounding of its corners, diminishes 
the power of every strokeflbr the space enclosed in the 
pencil line exactly represents the power of a stroke of the 
engine, with the exception of the lead corner, — lead being 
efficacious in the working of the engine. 



k 



244 HAND-BOOK OF LAND AND MARINE .ENGINES. 

How to Compute a Diagram. — Set down the length of 
the spaces formed by the vertical lines from the base, in 
measurements of a scale accompanying the indicator, and 
(m which a tenth of an inch usually represents a pound of 
pressure ; add up the total length of all the spaces, and 
divide by the number of spaces, which will give the mean 
length, or the mean pressure upon the piston in pounds 
per square inch. 

How to Calculate the Power the Engine is exerting 
when Ihe Diagram is taken. — Multiply the area of the 
piston by the mean pressure, as shown by the diagram ; 
multiply the product by the speed of the piston in feet per 
minute, and divide by 33,000. The quotient will be the 
indicated horse-power. 

Utility of the Indicator to Owners of Steam-Engines 
and Factories. — Disputes frequently arise between parties 
letting power and their tenants, in consequence of the 
latter using more power than that specified in the contract, 
and the price of which was fixed in the first place at so 
much per horse-power. Under such circumstances the 
question will arise, How much power is each tenant using? 
The only way to determine this accurately is by means of 
an indicator. 

Method of Determining how much Power each Tenant 
is actually using. — Throw off all the belts except the main 
or driving-belt, and take a set of diagj-ams from the engine, 
with no load on except the shafting ; then throw on the 
machinery of tenant No. 1, and take another set, and so 
on until all the machinery that is driven by the engine 
is in motion. Each set of diagrams will show the amount 
of power that each tenant is using, and by adding them 
together, they will show the aggregate work that the 
engine is performing. 

But, on the whole, it will be found to be less than would 



HAND-BOOK OF LAND AND MARINE ENGINES. 



245 



be shown by one set of diagrams taken with all the ma- 
chinery on. This arises from the fact that the friction of 
the engine and machinery decreases as the power required 
decreases. 




Diagram No. 4 was taken from an engine in very good 
21* 



246 HAND-BOOK OF LAND AND MARINE ENGINES. 

condition. The dotted line from E to F shows the boiler 
pressure, and from F to G, the theoretical curve. The line 
P, P, is the atmospheric line. The valve opens just as the 
crank is passing the centre ; and at the commencement of 
the stroke, the pressure of steam on the piston, S, ap- 
proaches close to the boiler pressure ; but, as the piston 
quickens its motion, the pressure urging it forward gradu- 
ally decrease^ to the point of cut-off, R, and from R to G 
the actual expansion curve approaches very closely to the 
theoretical curve. At G, the exhaust-valve opens, and the 
pressure drops to 1| pounds, which is steadily maintained 
until the piston reaches y, when the exhaust- valve closes, 
and the remaining steam in the cylinder is compressed 
until the crank reaches the dead centre, when the valve 
opens and another stroke is commenced. The line from i 
to y is called the line of counter-pressure, while the line 
from 2/ to ^ is the line of compression. 

Diagram No. 5 was taken from an engine that thumped 
badly from the first time it was started up, and after 
every other means were resortejd to to discover the cause 
of the knocking, the indicator was placed on the engine, 
and the diagram dotted line was obtained; by this in- 
formation the error was discovered and corrected. The 
engine then worked well, and gave the diagram shown by 
the full line on same cut. 

Diagram No. 6 was taken from a high-pressure engine 
working at a piston speed of 80 revolutions per minute. 
The lost power of this engine was found to be 20 horse- 
power, arising from back pressure, which was caused hy 
a weight on the exhaust-valve, placed there for the pur- 
pose of forcing the exhaust through a tank and 100 feet 
of inch pipe. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



247 



The steam-gauge com pared with the indicator was found 
to be correct ; and it was also found that there was a loss 
of^l7 pounds per square inch between the boiler and the 




248 



HAND-BOOK OF LAND AND MAEINE ENGINES. 



cylinder, in consequence of the imperfect action of the 
governor. 




m 



Diagram No. 7 was taken from an engine that was sup- 
posed to be all right, but, on applying the indicator, it was 



HAND-BOOK OF LAND AND MARINE ENGINES. 



249 





found that the steam that should have been admitted at 
C, was not admitted until the piston had advanced to D, 
more than one-eighth of the stroke; the valves were reset 
by the indicator, after which Diagram No. 8 was taken, 
which shows that it lacks very little of being perfect. 



250 HAND-BOOK OF LAND AND MARINE ENGINES. 

Diagram No. 9 was transferred from a card, taken from 
a Buckeye engine. Diam. of cylinder, 10 ; stroke, 18 ; rev., 
170. Steam pressure, per gauge, 84 lbs. ; initial pressure 
above air-line, 82 ; terminal vacuum, 18 ; main effective 
pressure, 30| ; clearance, 2i per cent, of stroke; cushion, 
8J; water per hour, per horse-power, 19 j^^^. 

Diagram No. 9, 




FORM OF DIAGRAMS. 

Were all engines constructed in the best possible pro- 
portion of valves, steam-passages, etc., and run at the 
proper speed for such proportion, and were the valves 
and pistons always tight, the same allowance made for 
clearance of piston, and no condensation of steam allowed 
in the cylinder, general rules might be given for the 
shape of diagrams from condensing and non-condensing 
engines, for each different pressure of steam and grada- 
tion of expansion. 

Thus, if steam were admitted freely from the boiler to 
the cylinder of a high-pressure engine during the whole 
stroke of the piston, the diagram should be nearly a 
parallelogram ; the upper line of which would represent 



HAIxD-BOOK OF LAND AND MARINE ENGINES. 251 

the pressure of the steam on one side of the piston, and 
the lower that of the exhaust steam on. the other side, and 
the ends of it would be described while the piston of the 
indicator was passing from one end of the cylinder to the 
other. Three of the corners of such a diagram might, as 
a general thing, be quite well-defined angles; but the 
fourth — that which is produced while the piston of the 
indicator is passing from the steam line to the exhaust — 
must be more or less curved, unless the engine was going 
very slow, or the ports extraordinarily large, as the con- 
tents of the cylinder of the engine must be discharged 
during the time this line is being described. 

Diagrams from condensing engines differ from those 
produced by non-condensing engines in the fact that in 
the latter the lower line, instead of being a little above 
atmospheric pressure, approaches nearly to that of perfect 
vacuum ; and, as the steam has to be condensed while the 
pencil is tracing the exhaust line, it is still more difficult, 
with such engines, to produce in the lines well-defined 
angles. There is also more or less of a curve produced at 
the termination of the vacuum line, owing either to the 
lead of the valves, or the compression of vapor as the 
valve approaches its seat. 

But nearly the whole of the area of the diagram lost 
from want of sharpness in the several parts, or their de- 
parture from right angles, except when it is the result of 
expansion, represents so much capacity of the engine for 
which there has been an expenditure of steam, and for 
which there has been no other consideration exchanged 
than the relief to the engine from the effects of the greater 
percussion produced by a more instantaneous charge of the 
force acting upon the piston. 

To produce a diagram with well-defined angles, it is 
evident that the pressure upon the piston of the engine must 
be changed from one side to the other, nearly or so far as tlio 



252 HAND-BOOK OF LAND AND MARINE ENGINES. ♦ 

usual diagram would show, quite instantaneously — a usage 
that few large engines would be able to stand. While 
economy of fuel, therefore, requires well-defined angles, the 
stability of the engine, or economy of repairs, must direct 
how nearly they may be allowed to approach them. 

In designating the quality of vacuum formed under the 
piston, there are two elements affecting it which ought to 
be noticed, viz.: the weight of the atmosphere, and the 
temperature of the water in the condenser at the time the 
diagram was made. For if the barometer stands at only 
28 inches, 30" of mercury being equivalent to 14*7 pounds, 
13*7 pounds would be a perfect vacuum ; and if the water 
in the condenser be at a temperature of 130^, its vapor 
will form a resistance of 2*17 pounds ; therefore the lowest 
attainable vacuum would be but 13*7 — 2'17=11'53 pounds ; 
whereas, if the barometer stood at 31", a perfect vacuum 
would be 15*2 ; and if the water was but 100°, its vapor 
would give a resistance of only '9, and consequently the 
highest attainable vacuum would be 15*2 — 7=14*3 pounds, 
making a difference of 2*77 pounds. 

The vacuum shown by the indicator will generally vary 
from that shown by the vacuum-gauge, when it is con- 
structed with a glass tube, hermetically sealed at the top ; 
for such gauges are designed to show the variation from a 
perfect vacuum, without reference to the weight of the 
atmosphere; but the vacuum shown by the indicator is 
affected by all its variations. 

HOW TO KEEP THE INDICATOR IN ORDER. 

After the indicator has been used, and before putting 
it away, it should be taken apart and carefully cleaned and 
dried, to prevent injury to the springs, and to keep the 
dust and dirt from scratching the cylinder and piston ; and, 
before using it again, the cylinder and piston, and the axis 



HAND-BOOK OF LAND AND MARINE ENGINES. 253 







22 



'lunnDB/v 



'Ui«9JS 



254 HAND-BOOK OF LAND AND MARINE ENGINES. 

of the paper cylinder, should be lubricated with some 
clean oil. If, in the use of the indicator, the cylinder or 
piston should be cut or scratched, so as to interfere with 
the freedom of its motion, they should be delicately scraped 
and burnished, or ground with some nicely prepared polish- 
ing powder or tripoli. 

THE DYNAMOMETER. 

The dynamometer is frequently employed instead of 
the indicator to measure the power transmitted from the 
engine to the machinery. In using the dynamometer, it is 
necessary to have the driving-pulley or band-wheel of the 
engine loose on the shaft, in order that it may move around 
freely. It is then connected by the springs of the dyna- 
mometer to a clamp, bolted firmly to the shaft, so that the 
strain on the band-wheel will cause it to turn on the 
shaft and act on the springs, producing a push or pull ; 
consequently, for every revolution the engine makes, an 
amount of power will be exerted which will be repre- 
sented by the strain, in pounds, on the springs connecting 
the driving-pulley to the clamp on the shaft. 

This strain multiplied by the number of feet through 
which the mechanism passes, and this number of foot- 
pounds multiplied by the revolutions per minute and 
divided by 33,000, will show the amount of work, in horse- 
power, that the engine is performing. 

To ascertain the power exerted by the engine of a screw- 
vessel, the thrust of the screw is made to bear upon the 
fulcrum of a lever of the second class, by receiving the 
force near the fulcrum ; and having a long arm for the 
weight, the force exerted by the screw is thus decreased in 
a great and easily ascertained ratio, somewhat after the 
manner by which, in the weighing-machine, a small weight 
in the machine-house balances a considerable one on the 
platform. 



HAND-BOOK OF LAKD AND MARINE ENGINES. 255 

Machinery very rarely transmits power uniformly from 
one locality to another ; which is particularly the case 
with the ordinary steam-engine, as the storage and delivery 
of work by a fly-wheel causes an irregularity in the power 
transmitted which can be measured by the dynamometer. 
But the dynamometer is best adapted for measuring the 
force of pulling a load on a road, a boat on a canal, or 
of towing a ship. The force in pounds indicated by the 
dynamometer, multiplied by the velocity in feet per second, 
will be the power in effect, which divided by 550 will 
give the horse-power in operation. 

The force driving a paddle-wheel is frequently measured 
by a dynamometer placed on shore, a rope being carried 
from the vessel and fastened to the dynamometer, when the 
engines are set to work, and their tractive force ascertained 
precisely as in the last case. The use of the dynamometer 
has greatly furthered the mechanical improvement of 
screw-engines by affording facilities to estimate the thrust 
of the screw, and thus ascertain if any large amount of 
force is being wasted. 

Rule joT finding the Dynamometrical or Effective Horse- 
power of a Marine Engine, — Having found (by the dyna- 
mometer) the number of pounds pressure exerted by the 
screw-shaft, multiply it by the speed of the ship in knots, 
and the product by 6080 (the number of feet in a knot) ; 
then divide the result by 60 (the number of minutes in 
an hour) and by 33,000, and the quotient will be the 
horse-power. 

Another Rule. — Multiply the number of pounds press- 
ure by the speed of the ship in knots, as before, and this 
product by '00307 ; the product will be the horse-power. 



2o(j HA]S"D-BOOK OF LAND AND MARINE ENGINES. 

THE ENGINEER. 

The skilful and practical engineer is a very important 
man, either in a manufacturing establishment, on a loco- 
motive, or on a steamship. And it can be safely said, 
that there are as many instances of genuine worth and 
ability to be found among engineers as in any other trade 
or profession — men who from small beginnings have 
worked themselves up to important positions, and have, 
by their intelligence and capability, not only won the 
respect of their employers, but of all with whom they 
have come in contact. 

Unfortunately, this is not so with all, as engineers are fre- 
quently met with who claim to know everything mentioned 
to them, and that they knew all about it long ago, or 
that they had a hand in originating the idea themselves. 
There is also a great tendency among persons having 
charge of steam-machinery, to look upon steam as some- 
thing very mysterious; and this tendency is not always 
confined to engineers who have the immediate charge of 
steam-engines and steam-boilers, but among those who, 
from ability or some other influence, occupy higher posi- 
tions. Now an engineer should be sure that his views are 
correct before putting them forth, and he should also be 
modest in expressing them, especially in the presence of 
his superiors. He may be able to teach others in his pro- 
fession, but in communicating his views, he should avoid 
making them feel that he assumes any superior knowledge. 
Men of superior ability generally prefer to show by their 
work what they know, and if a reason is asked for this or 
that, they are always ready with a clear and concise answer. 

The opportunities in this country for young engineers 
to rise are equalled in no other country in the world ; for 
this reason they should improve every opportunity to 



HAND-BOOK OF LAND AND MARINE ENGINES. 257 

qualify themselves for the responsible duties of their call- 
ing, as it is only by slow and careful study that they can 
arrive at the logical conclusions so essential to success in 
their profession. They must remember that it is not 
through inspiration that the expert attains more accurate 
results than the novice ; yet perhaps the former was once 
more awkward and rude in science than the latter, and 
only obtained his superiority and skill by close study and 
investigation. It frequently occurs, however, that the 
expert in engineering, as in all other professions, is only 
an expert in name. 

Fop this reason there is a strong prejudice in favor of 
those who are known to be practical men, in distinction 
from those who are called theoretical engineers. The 
practical engineer is understood to be one who relies 
entirely upon the information he has gained by his 
personal experience, while the so-called theoretical en- 
gineer is willing to accept the facts established by others, 
when they are well authenticated, and uses them to increase 
his knowledge. It is hardly necessary to state that of 
two men, each having the same natural intelligence, the 
one who employs his intellect, and adds the result of his 
studies to the knowledge that he has gained by experience, 
will in general be much the abler engineer of the two. 
It is true, that if he relies entirely upon theory untested 
by experiment, his views will be of little value, since that 
theory only is correct which takes account of all the 
conditions that occur in practice. 

The very nature of sea service calls for superior intelli- 
gence in those on whom depend the care and management 
of a ship's machinery, on account of the very serious nature 
of the results which may accrue from a failure of the power 
in an emergency. Engineers should, therefore, prepare 
themselves for any casualty that may arise, by consider- 
22^ R 



258 HAND-BOOK OF LAND AND MARINE ENGINES. 

ing possible cases of derangement, and deciding in what 
way they would act should certain accidents occur. The 
course to be pursued must have reference to particular 
engines, and no general rules can therefore be given ; but 
every marine engineer should decide on certain measures 
to be pursued in the emergencies in which he may be 
called upon to act, and where everything may depend 
upon his energy and decision. 

When engineers, or any other class of mechanics, fail to 
improve or qualify themselves to discharge the duties of 
their respective callings with ability and honor to them- 
selves, their trade is sure to degenerate, until, from being a 
profession or a science, it falls into the hands of incom- 
petents, and ceases to be anything more than a mere occu- 
pation. Ignorance among any class of mechanics is a great 
misfortune, but it is particularly so in the case of engineers. 

MANAGEMENT OP LAND AND MARINE ENGINES. 

Extensive as is the literature connected with the steam- 
engine, there is very little in print in relation to the prac- 
tical management of steam machinery. It is not difficult 
to discover the reason for this omission. The practical 
details are so varied, for the different cases that may 
arise, that it is almost impossible to classify them. 

Among the most important duties of a marine engineer 
are, the proper adjustment of the different parts of the 
machinery, and to see that they are neither too tight nor 
too slack, and that none of them becomes injured from 
heating. In the generality of marine engines, the bearing 
most apt to heat is the crank-pin ; but much depends on 
the proportions of the parts, which differ in different en- 
gines. But, as in most engines the crank-pin can be 
touched with the hand at each revolution, there can be but 
little excuse for allowing any serious heating at that point. 



HAND-BOOK OF LAND AND MARIKE ENGINES. 259 

In cases of extreme heating of the crank-pin, it is 

tisual to slack up on the keys, and lubricate the parts in 
contact with a mixture of sulphur and oil, or tallow, lead 
filings, or quicksilver ; but it sometimes becomes necessary 
to cool the heated parts with cold water applied by means 
of a hose communicating with the deck-pumps. Such ex- 
treme heating rarely occurs, except when the keys are too 
tightly driven, or the regular supply of oil neglected. 

When pillow-blocks, or main bearings, become trouble- 
some from heating, the annoyance, in a majority of cases, 
can be remedied by mixing a quantity of Bath brick-dust 
with water, and running it through the holes in the caps 
when the engine is in motion, as it has a tendency to 
smooth off the surfaces in contact, and bring them to a 
solid bearing. In cases where heating of the heavy revolv- 
ing parts is induced by grit, or such foreign substances as 
are frequently found in inferior qualities of oil, the diffi- 
culty may be removed by using a strong solution of pot- 
ash, or concentrated lye, on the parts affected while they 
are in motion. They should be thoroughly lubricated 
immediately after the solution is applied. 

Looseness in any of the revolving parts generally 
manifests itself by a knock ; but the keys of the parts that 
only vibrate may drop out and cause serious damage, with- 
out giving any warning ; for this reason, when the keys 
are properly adjusted, the set-screws should be screwed up 
sufficiently tight to prevent the possibility of the key 
moving backward or forward. Generally speaking, keys 
have a tendency to work further in, which frequently 
causes serious heating before the engineer is aware of it. 

While the vessel is in port, the bonnets and casings of 
the steam -chest should be removed for the purpose of 
examining the valves, faces, and seats, and if any hard or 
cut places be found they should be carefully scraped and 



260 HAND-BOOK OF LAND AND MARINE ENGINES. 

refitted. The crank should then be placed on the top and 
bottom centres, with the go-ahead gear in position, in order 
to see whether the valves open and close at the right time, 
or if they have the proper amount of lead. 

The piston should frequently be removed from the cyl- 
inder, and the faces of the rings, where they form the 
joints with the flange of the piston-head and the follower- 
plate, reground and fitted, and the spring packing re- 
adjusted. The tightness of the piston should also be 
proved, by admitting steam above or below it, and open- 
ing the indicator's cocks on either side, to see if any steam 
escapes ; in such cases, the injector-cocks should be slightly 
opened an instant, to withdraw any steam that may have 
collected on the opposite side of the piston, so that the 
passage of any steam may be more readily perceived. The 
tightness of most parts of the engine may be tested in this 
way without moving it more than half a stroke. 

The link-motion should next receive special attention, 
for the purpose of ascertaining if the link, link-block, link- 
pins, eccentric - straps or rods, need readjustment or re- 
pairs. The screw-shaft should also be carefully examined, 
to determine if lining-up is required, or if the gland or 
any part has become badly worn or seriously cut. 

The air-pump cover should then be lifted, and the 
bucket withdrawn, for the purpose of ascertaining if the 
foot-valves are in good order. The condenser should also 
be proved, which can be done by taking oflT the door or 
doors, and filling it with cold water ; and should any leak 
be discovered, the tube or tubes should be removed and 
repaired or replaced with new ones. Every engineer 
should make himself perfectly familiar and conversant with 
all the details of the surface condenser. 

The state of the vacuum will be shown by the vacuum- 
gauge attached to the condenser ; and if it be imperfect, 



HAND-BOOK OF LAKD AKD MARINE ENGINES. 261 

the cause must be ascertained and the fault corrected. 
If the hot - well be much more than blood - warm, more 
injection water must be admitted ; and if the vacuum is 
still imperfect, there must be some air leak, which the en- 
gineer must endeavor to discover. Very often the fault 
will be found to lie in the valve or cylinder cover, which 
must then be screwed down more firmly, or in the faucet- 
joint of the eduction-pipe, the gland of which will require 
to be tightened, or the leaking part puttied up. The cyl- 
inder and valve stuffing-boxes may at the same time be 
supplied afresh with tallow, and the door of the con- 
denser examined. The joints of the parts communicating 
with the condenser are usually tried with a candle, the 
vacuum sucking in the flame if the joint be faulty. 

When a leakage of air into the condenser, or its con- 
nections, has been discovered, it may be stopped tempo- 
rarily by calking in spun -yarn, or driving in thin fine 
wedges ; if the leakage be into the condenser, it is some- 
times convenient to allow water to be injected through the 
orifice, by which means little harm is done. In several 
cases where, during a long voyage, the bottom of the con- 
denser has become leaky by corrosion, (often induced by 
galvanic action with the copper bolts of the ship's bot- 
tom, as well as the brass foot-valve, etc.,) a water-tight 
crank has been constructed at sea between the side keelsons. 
By this means, the condenser and air-pump are submerged 
in a kind of well constantly replenished with cold water 
from the sea, which, forcing its way through the leaks by the 
pressure of the atmosphere, shares with the proper injec- 
tion water the duty of condensing the steam — the injec- 
tion-cock orifice being partially closed in proportion to the 
extent of the leakage through the bottom. 

When the vessel is laboring in a heavy sea, the supply 
of injection water should be diminished; for in such cases, 



262 HAND-BOOK OF LAND AND MARINE ENGINES. 

where the speed of the engines is subject to great and con- 
stant fluctuations, depending upon the greater or less sub- 
mersion of the wheels or screw-propeller, the condenser is 
liable to become choked with water, thereby causing the 
engines to stop. The effect of working the engines with a 
stinted supply of condensing water is, of course, that the 
condensers will become hot, and the vacuum will be dimin- 
ished ; but this is a minor evil in comparison with endan- 
gering the machinery by subjecting it to too severe a strain. 

Cape must be taken, when the engines make a tempo- 
rary stoppage, that the injection -cock or air-pump does not 
leak, and allow the condenser to fill with water, which 
causes much trouble and delay in starting the engines 
again ; so, should this be apprehended, the sea-cock must 
also be closed at the same time with the injection-cock. 

When a stationary engine is stopped, even for a short 
time, the cylinder drip-cocks should be immediately opened, 
in order to allow the water of condensation to escape. 
They should not be closed until after the engine has been 
started. Before starting any engine, if it has been stand- 
ing still for some time, the cylinder should be warmed by 
admitting steam, and working the engine back and forth 
with the starting-bar. This is a necessary precaution 
against the dangers arising from an accumulation of water 
in the cylinder induced by the steam coming in contact 
with the cold iron. 

The oil OP tallow intended to lubricate the cylinder 
and valves should not be admitted until after the engine 
has been in motion and the drip-cocks closed ; as, other- 
wise, instead of being returned with the exhaust, and 
lubricating the rubbing surfaces, a portion of it would be 
driven out with the water of condensation, and lost. 

In setting up, repairing, or driving the keys of steam- 
engines, a soft hammer or piece of hard wood should 



HAND-BOOK OF LAND AND MARINE ENGINES. 263 

invariably be used to drive the parts fast together. But, 
in the absence of either, a piece of sheet copper or brass 
should be interposed between the face of the hammer and 
the part to be driven. Any engineer can make himself a 
soft hammer by cutting a hole, for the handle, through a 
piece of brass or copper tube about two inches in diameter 
and four or five inches long, and, after inserting the handle, 
filling the tube with Babbit-metal or lead. 

Raising Steam and Getting under Way. — The first 
duty of the engineer, preparatory to getting under way, 
is to fill the boilers with water to the upper gauge-cock. 
If they be located in the hold, it will be only neces- 
sary to open the blow-cock, and the water will flow into 
the boilers through the bottom of the vessel, otherwise 
it will be necessary to fill them by the hand force-pump ; 
although donkey-pumps having separate boilers are most 
frequently used for that purpose. 

The next step is to start the fires, which should be 
allowed to burn slowly, in order that all parts of the 
boiler may expand uniformly, and the safety-valve be 
kept open for the purpose of allowing the air to escape 
from the boilers. As soon, however, as steam begins to 
escape through the safety-valves, they should be immedi- 
ately closed, for then the air is all expelled, an atmosphere 
of steam having taken its place. 

When the steam-gauge shows any excess of pressure 
over the atmosphere, the valves may be raised, and steam 
allowed to flow into the cylinder and through all the pipes ; 
this expels the air and warms the cylinder, and prevents 
the condensation of steam when the engine is started. 

When sufficient steam is shown by the gauge to work 
the air-pump and produce a vacuum, say 6 or 6 pounds, 
the injection-cocks should be opened a little, and the ec- 
centric-hook unshipped, and the valves moved back and 



264 HAND-BOOK OF LAND AND MARINE ENGINES. 

forth with the starting-bar or the link, as the case may be, 
in order to produce a reciprocating motion in the piston. 
The engine should then be " turned over " two or three 
times for the purpose of seeing if everything is all right. 
If everything is found to be in perfect order, the engine 
is stopped, the oil-cups filled, and all the rubbing and 
revolving surfaces thoroughly lubricated ; then the vessel 
will be ready to proceed on her voyage. 

When it becomes necessary to stop the engine, the steam 
is first shut oif, or nearly so ; the supply of injection water 
diminished, the eccentric-catch unhooked, and the valves 
worked by hand ; the damper in the chimney should also 
be closed, and the furnace-doors opened. 

To back an engine, where only one eccentric is used, 
the steam is first shut ofi*, the eccentric-hook thrown out 
of gear, and steam admitted to the opposite end of the 
cylinder by means of the starting-bar. If the link be 
employed, it is only necessary to shift it to the backward 
motion. 

Every ocean steamer should carry a liberal supply of 
duplicates of the parts that would be most likely, in case 
of breakage, to disable the engine. They should also 
have a good supply of bolts, nuts, and washers, packing- 
solder, charcoal, portable forges, hammers, wrenches, 
spanners, screw- and monkey-jacks, ratchets and ratchet- 
drills, cold chisels, key-sets, files, reamers, pinch-bars, 
straight edges, T squares, brass-sheaved blocks, and all 
such tools as would be likely to be called into play in any 
emergency, which should be hung up or stored in con- 
spicuous, convenient, and accessible places, for, unless this 
be done, they are liable to become mislaid or eaten up with 
rust, as neglect generally follows their stowage in unfre- 
quented or obscure places.* 

* See page vi. 



HAND-BOOK OF LAND AND MAEINE ENGINES. 265 

HOW TO PUT THE ENGINES IN A STEAM-BOAT OR 

SHIP. 

The art of placing engines in ships is more a piece of 
plain common sense than any other feat in engineering ; 
consequently, every engineer that engages in such an un- 
dertaking must settle a mode of procedure for himself, as 
it would be impossible to give any general instructions for 
such work that would meet all the requirements of the 
varying circumstances of each individual case. But as 
the subject is one of great interest and importance to 
engineers, it may not be out of place to offer some general 
observations upon it, together with specific directions in 
such particulars as seem to require them ; the most prac- 
tical mode of procedure being as follows : 

The first business of the engineer is to ascertain the 
precise beam centre of the boat. He then erects perpen- 
dicular straight-edges towards each end of the boat, suffi- 
ciently far apart to clear the cylinder at one end and the 
shaft and crank at the other. These straight-edges must 
rise strictly perpendicular to the side level of the boat, be- 
cause they are to serve as a guide in establishing the sidewise 
centre lines of the cylinder, gallows frame, walking-beam, 
and main connecting-rod ; and, indeed, must be kept in view 
in the whole operation of placing the engine in the boat. 

The manner of placing a straight-edge in its true posi- 
tion is, to rest the lower end upon the centre keelson, in 
such position that one side of the piece forming the 
straight-edge shall be exactly in the beam centre of the 
boat. To carry up the straight-edge in strict perpendicu- 
lar from this centre, a straight-edge must be laid also 
across the boat, at the level of the deck, resting in an 
exact horizontal position by means of blocks placed under 
each end, at the sides of the boat. The exact position of 
23 



266 HAND-BOOK OF LAND AND MARINE ENGINES. 

the perpendicular straight-edge may now be ascertained, 
either by means of a T square or by measuring from the 
outside of the hull towards the centre. 

Having found the position of one perpendicular straight- 
edge by the means described, the second will of course be 
fixed in an exact relative position to the first. The proper 
height of the gallows frame, where the pillow-block rests 
upon it, must now be measured from the flooring of the 
boat upon which the engine keelsons rest. This height 
must always be specified in the working drawings of the 
engine, to which reference must be had ; and having been 
measured on either side, that side of the gallows frame 
must be cut oS* at the proper point to receive the beam 
pillow-block. A T square applied to the side that has 
thus been cut off will indicate the point of cutting off the 
other side of the gallows frame, bringing both sides to 
exactly the same height. In applying the T square for 
this purpose, care should be taken to keep the long or per- 
pendicular arm of the square in exact line with the per- 
pendicular straight-edges above mentioned. 

The beam pillow-blocks can now be placed in their 
positions, precaution being taken to see that these blocks 
are of equal dimensions from the point resting upon the 
gallows frame to the centre of the journal, any difference 
to be obviated by the variation of the height of either 
side of the gallows frame from the exact point heretofore 
reached. A beam main centre piece of wood must next 
be made of the same dimensions as the beam centre itself. 
This wooden beam main centre piece must be placed in 
the journals of the beam pillow-blocks. The middle of 
this centre piece, measured from each journal, and indi- 
cating the beam centre of the working-beam, must be 
marked upon it, either by the person turning it or by the 
engineer himself, usually by the former. 



HAND-BOOK OF LAND AND MARINE ENGINES. 267 

A piece of small cord, of very perfect manufacture and 
very strong (catgut is generally used), must now be em- 
ployed, stretched from one straight-edge to the other. A 
short straight-edge may also be fastened, with screws, to 
the wooden centre piece, exactly at the middle thereof, 
indicating the beam centre of the working-beam. This 
centre line must correspond with the catgut line drawn 
from the two straight-edges. The wooden centre piece 
should be brought to rest in exact right angles to the 
several centre lines of the working-beam ; that is, in right 
angle to the horizontal, perpendicular, and beam centres of 
the working-beam, as heretofore ascertained and described. 

Having described the manner of ascertaining the 
various points to be considered in fixing the beam pillow- 
blocks in their places, the work becomes merely mechanical, 
and will be accomplished by such means as suggest them- 
selves to the engineer; which done, the beam pillow-blocks 
may be permanently bolted to the top of the gallows frame. 

The laying of the bed-plate is the next object to receive 
the attention of the engineer. The bed-plate is laid on 
two oak planks, which may easily be adjusted to accom- 
modate the variations in the bed-plate. The planking 
which lies on the engine keelson, and comes in immediate 
contact with the bed-plate, should be adjusted as nearly as 
possible to its proper position. This may be done with the 
use of a T square. The exact centre of the steam-cylinder 
must now be taken into consideration, and, keeping that 
point in view, the bed-plate can now be placed upon the 
planking prepared, as above referred to, for its reception. 

The centre points where the condenser and air-pump 
rest upon the bed-plate must now be accurately ascer- 
tained, and again the T square must be employed to lay 
the bed-plate true in every direction. This being accom- 
plished, a line must be stretched from the two upright 
straight-ed^es before described, and the air-pump and con- 



268 HAND-BOOK OF LAKD AND MARINE ENGINES. 

denser centres must be in accordance with this line. Now 
fix the true perpendicular centre line of the gallows frame, 
and measure from that line to the centre line of the cyl- 
inder, as established in the working drawing. This will 
settle the exact position of the bed-plate. 

The relative positions of the beam centre, as indi- 
cated by the cord drawn from the two upright straight- 
edges, and of transverse centres of the cylinder, con- 
denser, and air-pump, must be indicated by marks with 
a chisel upon the ends and sides of the bed- plate flanges, 
preparatory to the removal of the cord when the condenser 
is placed in position. Before doing this, however, four 
marks on the upper and lower flanges of the condenser 
must be made with a chisel, at right angles to each other, 
corresponding w4th the centre of the condenser. This 
centre is ascertained by means of a wooden cross placed in 
the condenser, the arms of the cross fitting closely to its 
inside diameter. The same marks, by the same process, 
must also be made on the upper and lower flanges of the 
steam-cylinder. 

The condenser may now be fitted to its place, care 
being taken to bring the centre at the top in exact posi- 
tion, measuring from the centre line of the gallows frame 
as before,' and in accordance with the line drawn from the 
two straight-edges ; in other words, that the centre line of 
the condenser is in exact perpendicular. The work of 
fitting the condenser to the bed-plate must, of course, be 
performed upon the " chipping-strips " in the lower flange 
of the condenser ; and when perfected, the condenser may 
be permanently bolted to its place. 

The cylinder bottom is always bolted to the cylinder, 
and when thus joined, the two are placed together upon 
the condenser. The marks upon the outside of the flanges 
will assist in bringing the lower part of the cylinder to its 
43xact centre point. The cylinder must now be fitted to its 



HAND-BOOK OF LAND AND MARINE ENGINES. 269 

place, care being taken, as in the case of the condenser, to 
maintain the perpendicular of its centre, the same rules 
governing both cases. 

The slides fop the cross-head must next be fitted to 
their places. To this end, a wooden cross must be placed 
in the lower extremity of the cylinder, the arms fitting 
closely to its inside diameter. A temporary platform, near 
the top of the gallows frame, must now be employed, to 
which a cord should be stretched from the centre point of 
the cylinder marked on the wooden cross in the cylinder. 
This cord should indicate a continuation of the true per- 
pendicular centre line of the cylinder, for the purpose of 
fixing the true position of the slides. In fixing the posi- 
tion of the slides, a wooden piece may be employed to 
represent the cross-head, with a point in the centre to 
show where the continuation of the centre line of the cyl- 
inder should pass ; and when the slides are accurately set, 
they should be bolted to the flanges of the cylinder. 

A brace must now be fitted to the upper flanges of the 
slides, to retain them in their proper position. And braces 
should be extended from the slides to the gallows frame. 
There should also be a diagonal cross-brace connecting the 
flanges of the slides with the other side of the gallows frame. 
Four more braces, two on each side, must be extended di- 
rectly from the slides to the gallows frame. All these 
braces must be bolted to the flanges of th^e slides and to 
the gallows frame. 

The piston, with piston-rod and the cylinder cover, may 
now be put in their places^ and then the cross-head put in 
its place and fastened to the piston. The working-beam, 
also, may be laid in the beam pillow-block journals. 

The setting of the main shaft and out-port pillow- 
blocks is the next work in order. A cord must be ex- 
tended, indicating the centres of these pillow-blocks. 
23* 



270 HA:^rD-BOOK of land and marine engines. 

These centres are to be ascertained by measuring the 
height, on the working drawings, from the top of the floor- . 
ing of the hull to the centre of the shaft, then drawing a 
horizontal line with a cord from the straight-edge to the 
perpendicular centre of the gallows frame at the height 
of the main shaft. A line must now be drawn perpendicu- 
larly through the centre of the shaft, parallel, in every 
direction, with the centre line of the cylinder, when a T 
square can be employed in determining the centre line of 
the main shaft, to be indicated by a cord drawn from one 
out-port pillow-block to the other ; the actual height, as 
well as the distance from the centre of the gallows frame, 
having been, as previously stated, ascertained by measur- 
ing the height, in the working drawing, from the flooring 
of the boat, and in using the T square, to see that this 
line is in strict right angle to the cord drawn from the' 
straight edge to the centre of the gallows frame, and also 
in right angle to the perpendicular line parallel to the 
centre of the cylinder. 

The placing of the main and out -port pillow-blocks 
must now be proceeded with. The engineer must measure 
the distance from the centre of the journals to the lower 
edges of the pillow-blocks, to ascertain the exact height of 
the resting-places of them above the flooring of the boat, 
when he will cut the timbers accordingly, with a view to 
the exact height of the centre of the shaft, fitting these 
timbers to the lower sides of the pillow-blocks. 

The centres of the journals of the out-port pillow- 
blocks must always be slightlj^ higher than the centre of 
the journal of the main pillow-blocks, on account of the 
great weight of the paddle-wheels, and the fact that the 
sides of the boat will yield more than the centre to the 
weight of the engine. If the two parts of the shaft, as 
usually employed in river -boats, lie perfectly true, the 



HAND-BOOK OF LAND AND MARINE ENGINES. 271 

cranks will show no variation in their distances from each 
other at any point in their revolution. 

In placing the air-pump in its seat, reference must be 
had to the working drawing, following the centre points, 
etc., as there laid down, subject, of course, to the forma- 
tion of the bed-plate. Mechanically, the operation is pre- 
cisely the same as in placing the condenser and cylinder. 
It is well to fasten a piece forming a straight - edge along 
the engine keelson, the upper or straight-edge of this piece 
to be in strict right angle to the perpendicular centre line 
of the cylinder ; with the aid of a T square, this straight- 
edge will supply the place of the perpendicular straight- 
edges before described, in case their removal should be- 
come necessary from any cause. 

The bed -plate is laid upon a mixture of white and red 
lead spread carefully over the oak planks which come in 
immediate connection with the bed-plate. The object of 
this mixture of paint is to fill up all the crevices or imper- 
fections of any character which may exist, either in the 
surface of the bed-plate itself or in the planking, causing 
the bed-plate to receive equal and substantial support in 
all its parts. The same process must be followed in laying 
the main and beam pillow-blocks ; these important parts 
of tne engine frequently having been broken in conse- 
quence of not being set firmly and accurately in their 
places. A layer of red lead is also employed to secure a 
perfectly tight joint between the condenser and bed-plate, 
after which a rust cement, composed of cast-iron turnings, 
pulverized sal-ammoniac, and flour of eulphur is calked 
into the joint to render it perfectly air-, steam-, and 
water-tight. 

SCREW-PROPEI.LERS. 

The screw- propeller, so commonly applied to the pro- 
pulsion of vessels, consists of two, three, or four helical 



272 



HAND-BOOK OF LAND AND MARINE ENGINES. 



or twisted blades, set upon a shaft or axis, revolving be- 
neath the water at the stern. The shaft where it protrudes 
through the stern of the vessel is surrounded by astuflSng- 




Screw-Propeller, 



HAND-BOOK OF LAND AND MARINE ENGINES. 273 

box, containing hemp packing, whereby the entrance of 
the water into the vessel is prevented, and the extremity 
of the shaft in the rear of the screw is supported in a 
socket or bearing attached to the rudder-post. This part 
rests upon the keel, and from it the rudder is suspended. 

The screw revolves in that thin part of the stern of 
the ship which is called the dead wood, in which a hole 
of suitable dimensions is cut for its reception ;. and the 
thrust or forward pressure caused by the action of the 
screw upon the water is transmitted to some point within 
the vessel which can be amply lubricated. It is the thrust of 
the shaft which is operative in propelling the vessel, and the 
amount of this thrust can be measured by means of a dyn- 
amometer applied to the end of the shaft within the vessel. 

The diameter of the screw is the diameter of the circle 
described by the arms ; and the length of the screw is the 
length which the arms occupy upon the revolving shaft. 
If a string be wound spirally upon a cylinder, it will form 
a screw of one thread ; if two strings be wound upon a 
cylinder with equal spaces between them, they will form a 
screw of two threads ; three strings similarly wound will 
form a screw of three threads, and so of any other number. 

If, instead of strings, flat blades be wound edgewise 
around the cylinder, and each blade has one of its edges 
attached to the cylinder by welding, soldering, or other- 
wise, then, if a slice be cut off the end of the cylinder, 
there will be only one piece of blade attached to that 
slice, if the screw be of one thread ; two pieces of blade, 
if the screw be of two threads ; three pieces of blade, if 
the screw be of three threads, and so of any number. 
The number of blades, therefore, of any screw determines 
the number of threads of which it is composed, and this 
indication equally holds however thin the slice cut off the 
end of the screw may be. 

S 



274 HAND-BOOK OF LAND AND MARINE ENGINES. 

The pitch of a screw is the distance measured in the 
direction of the axis between any one thread and the 
same thread at the point where it completes its next con- 
volution. Thus, a spiral staircase is a single-threaded 
screw, and the pitch of such a screw is the vertical distance 
from any one step to the step immediately overhead. 

Ordinary screw-propellers are not made nearly so long 
as what answers to a whole convolution ; and in speaking 
of their pitch, therefore, it is necessary to imagine the 
screw to be continued through a whole convolution at the 
same angle of inclination with which it was begun. Of 
this whole convolution any given proportion may be em- 
ployed as a propeller, and the length of a screw, therefore, 
cannot be determined from the pitch, neither can the 
pitch be determined from the length. 

The form of screw most frequently employed in this 
country is a screw of two blades or threads, sometimes 
three or four blades are used. The pitch of the screw is 
not made less than its diameter, sometimes nearly twice 
the diameter, and in some instances over twice the diameter 
of the screw. The length of the screw is usually made 
equal to one-sixth of the pitch. The thrusting of the 
screw is measured by the area of the circle described by 
the arms, which is termed the area of the screw-disk. 
The screw-disk has generally about one square foot of 
area for every 2 J or 3 square feet in the immersed trans- 
verse section of the vessel. 

NEGATIVE SLIP OP THE SCREW-PROPELLER. 

By " slip " is meant the difference between the actual 
advance of the propeller through the water and the ad- 
vance which would be accomplished, if there were no 
recession of the water produced by the pressure of the 
propelling surface. 



HAND-BOOK OF LAND AND MARINE ENGINES. 275 

A screw of 10 feet, if working in a stationary nut, 
would advance 10 feet for every revolution it performed ; 
but when such a screw acts in the water, it may only ad- 
vance 9 feet or less for every revolution — the water being, 
during the same time, pressed back one foot, from its 
inertia being inadequate to resist the moving force. In 
such a casej the slip is said to be 1 foot in 10, or 10 per 
cent. 

With every kind of propeller which acts upon water, 
there must be a certain amount of slip, for any force, 
however small, will overcome the inertia of the water to a 
certain extent ; but, by so proportioning the propelling 
apparatus that it will lay bold of a large quantity of 
water, the backward motion of the water will be small 
relatively with the forward motion of the vessel ; or, in 
other words, the slip will be reduced to an inconsiderable 
amount. 

One of the most remarkable phenomena connected 
with the action of the screw is, that under some circum- 
stances its apparent progress through the water is not only 
as great as that of the ship, but greater. In some of the 
early experiments with the screw, when the vessel was 
proceeding under the joint action of steam and sails, it 
was found that the progress made by the vessel through 
the water was greater than if the screw worked in a solid 
nut. It was from this inferred that the ship must be over- 
running the screw; yet it was plain that this could not 
be the case, as the engine was travelling at the usual 
speed; but investigation of the subject explains the 
phenomena, and ascribes it to the fact of the screw work- 
ing in a column of water which follows the ship, instead 
of in the stationary water of the sea. 

When a strong current of water runs through the 
arches of a bridge, the water may be observed to curl 



276 HAND-BOOK OF LAND AND MAHINE ENGINES. 

around those ends of the piers which stand lowest in the 
stream ; and if a chip of wood be thrown into that spot, 
it will not be carried off by the stream, but will remain at 
rest, showing that the water is not in motion in that place. 

Now, suppose a screw to be placed in this stationary- 
water, it will be obvious that any movement of rotation 
given to it will produce some thrust upon the screw-shaft ; 
whereas, if the screw were placed in the stream, it would 
require to revolve faster than the stream runs, before any 
thrust upon the screw^shaft could be produced. 

Now, suppose the pier to be a ship, the other circum- 
stances specified will not be altered thereby; and it is 
conceivable, that a screw acting in this dead water might 
aid the vessel to stem the current, even though the screw 
moved with less velocity than that of the current itself. 

That the screw will exert some peaching force upon 
this dead water, even with any speed of rotation, is ob- 
vious enough ; but whether, with a speed inferior to that 
of the stream, it will produce a sufficient thrust to enable 
the vessel to stem the current, will depend very much 
upon the shape of the vessel and the dimensions of the 
screw employed. 

If the pitch be fine, and the number of revolutions 
answering to a given speed of vessel be great, there will be 
a tendency to pile up the water at the stern, owing to the 
adhesion of the water to the rapidly revolving blades, and 
the consequent acquisition of a considerable centrifugal 
force by the water. When this action occurs, the vessel 
will be forced forward, to some extent, by the hydrostatic 
pressure produced by the elevation of the water at the 
stern, and this pressure will aid the thrust of the screw\ 
If, then, by such an arrangement, a vessel could be made 
to stem a current, she could obviously, under like condi- 
tions, be made to move through still water. 



HAND-BOOK OF LAND AND MARINE ENGINES. 277 

All vessels carry a cftirrent in their wake which answers 
to the dead water in the case of the bridge ; and if a screw 
acts in this current, then the apparent slip will be positive 
or negative, just as the real slip, or the velocity of the 
current, may preponderate. In every case, the screw must 
have some slip relatively with the water in which it acts ; 
but if that water has itself a forward motion, the result 
cannot be the same as if the water were stationary, and it 
will be necessary to reckon the forward motion of the 
current as well as the forward motion of the slip. 

Thus, if the peal slip of the screw be three miles an 
hour, and the following current runs at the rate of three 
miles an hour after the ship, then there will appear to be 
no slip, if the comparison be made with the open ocean 
on each side of the vessel ; or' there will appear to be a 
negative slip, as it is termed, of one mile an hour, if the 
following current runs at the rate of four miles an hour. 
The whole perplexity vanishes, if we consider that a cur- 
rent follows the ship at a rate which may be greater or 
less than the slip of the screw. This current is confined 
to the water very close to the ship, so that a log, whether of 
the ordinary or the patent kind, will not take cognizance 
of it if thrown over the stern. 

The centrifugal action of the screw, it appears not 
improbable, besides piling up the water at the stern, and 
thus forcing the vessel on with a velocity which may be 
greater than that of the screw, also causes a current of 
water to flow radially from the centre of the screw to its 
circumference ; and this stream of water, by intervening 
between the surface of the screw and the nut of water in 
which it works, may assist in making the vessel travel 
faster than the screw itself. 

In all screw-vessels, the slip is greater than is generally 
supposed ; for in all of them there is a following current 
24 



278 HAND-BOOK OF LAND AND MARINE ENGINES. 

in which the screw works ; and as, in some cases, the cur- 
rent conspires to make the apparent slip to disappear alto- 
gether, so it will, in every case, reduce the visible slip to 
a less amount than the real slip, and it is the real slip 
w^hich it concerns us to determine. There is no benefit 
derived from the existence of a following current in screw ' 
vessels, for to produce the current requires a large ex- 
penditure of power; and in screws so proportioned as 
to produce a negative slip, a poorer performance has been 
obtained than in cases in which screws producing an ap- 
parent slip of 10 to 20 per cent, have been employed. 

The Screw as compared with the Paddle. — Under 
favorable circumstances, there is but little diiference be- 
tween screws and paddles. In running before the wind the 
paddle has the advantage ; but when the wind is ahead, it 
is not so, for the wind acts on the paddle-boxes, which 
offer great resistance and retard the ship. The superiority 
of the screw is shown in long voyages ; for, whereas the 
lightening of the ship proves detrimental to the paddle, 
it cannot be so to the screw, the screw being more deeply 
immersed. The screw requires deeper water than the pad- 
dle. In ships of war, the screw gives a clear broadside, 
while the paddles occupy room that should be devoted to 
the guns. The vibration of ships propelled by the screw 
is greater than in those using the paddle, though the latter 
roll more in stormy weather. 

Twin Screws. — Twin screws are simply two screws, one 
on each side of the rudder, instead of one screw in the 
dead wood in front of the rudder. One screw turns to the 
right and the other to the left. It is claimed for this 
arrangement, that the ship can be very quickly turned 
within a small space. 

Two-bladed screws are claimed to be more efficient 
than those with three or four blades, but repeated experi- 



HAND-BOOK OF LAND AND MARINE ENGINES. 



279 



ments have shown that, in point of efficiency, there is very 
little difference between them. . Two-bladed screws should 
be made with a shorter pitch than those having three or 
four blades. 

TABLE 

OF THE PROPER PROPORTIONS OF SCREW-PROPELLERS. 



Screws of Two Blades. 


Screws of Four Blades. 


Screws of Six Blades. 


Ratio of 


Fraction 


Ratio of 


Fraction 


Ratio of 


Fraction 


Pitch to 


of 


Pitch to 


of 


Pitch to 


of 


Diameter. 


Pitch. 


Diameter. 


Pitch. 


Diameter. 


Pitch. 


1.006 


0.454 


1.342 


0.454 


1.677 


0.794 


1.069 


0.428 


1.425 


0.428 


1.771 


0.749 


1.135 


0.402 


1.513 


0.402 


1.891 


0.703 


1.205 


0.378 


1.607 


0.378 


2.009 


0.661 


1.279 


0.355 


1.705 


0.355 


2.131 


0.621 


1.357 


0.334 


1.810 


0.334 


2.262 


0.585 


1.450 


0.313 


1.933 


0.313 


2.416 


0.548 


1.560 


0.294 


2.080 


0.294 


2.600 


0.515 


1.682 


0.275 


2.243 


0.275 


2.804 


0.481 



MEASUREMENT OF THE SCREW-PROPELLER. 

The surface of a screw-propellep is the same as would 
be generated by a line revolving around ' a cylinder, 
through the axis of which it passes, and at the same time 
advancing along the axis. In this way the under or back 
surfaces of the blade may be supposed to be formed, and 
then the proper thickness is put on, so as to make the 
front or entering surfaces. 

All measurements of a blade should, of course, be made 
on the back surface. It will be evident, from the explan- 
ation of the manner in which the surface of a blade is 
formed, that by varying the shape of the generating line, 
or at the rate of its motion along the axis, very different 
forms of blades can be produced. The pitch of a screw is 
the distance the generating line moves in the direction of 



280 HAJSD-BOOK OF LAND AND MARINE ENGINES. 

the axis while it is making one revolution around the 
cylinder. 

It is evident from this that the pitch of the screw may- 
be constant throughout, or it may vary from forward to 
after part of the blade, or from, hub to periphery, accord- 
ing to the rate of motion of the generatmg line in an axial 
direction, and its angle of inclination to the axis. Hence, 
in measuring a screw-propeller, it will be necessary to de- 
termine the pitch at a number of points, for the purpose 
of ascertaining whether it is variable or constant. 

Every point in the generating line describes a curve 
which is called a helix. If measurements are taken along 
one of these helices, they will show whether the pitch 
varies from forward to after part of the blade, and meas- 
urements on corresponding points of different helices will 
indicate whether or not the pitch is constant from hub to 
periphery. As a general thing, the hub of a screw-pro- 
peller is faced off at the ends, and the blades do not over- 
hang a plane passing through this face. If necessary, 
however, a faced surface can be fitted to the hub, and 
made thick enough for its plane to clear the blades. 

Provide a straight-edge a little longer than the radius 
of the propeller, and secure cleats to it at every foot of 
its length for large wheels, and from six to nine inches 
apart for small wheels. These cleats are intended to serv^e 
as guides for a rule, so that measurements can be made 
with accuracy at right angles to the straight-edge. Secure 
to the end of the hub a piece of paper on which the centre 
of the hub is marked, and the circumference is divided 
into any number of equal parts. 

Then place the straight-edge on the end of the hub, 
bringing a mark near its end to the centre of the hub, 
and making its direction coincide with a division of the 
circumference. Measure the perpendicular distance from 



HAND-BOOK OF LAND AND MARINE ENGINES. 281 

the straight-edge to the surface of the blade at each one 
of the cleats ; then move the straight-edge to coincide with 
the next division of the circumference, and again take 
measurements. 

Suppose that the circumference of the hub be divided 
into thirty-two equal parts, and that the measurements 
from the straight-edge to the blade, taken at each cleat, 
are each six inches, then move the straight-edge to the 
next position, and suppose that the measurements are each 
fourteen inches. This shows that the generatrix, in one 
thirty-second of a revolution, has advanced eight inches in 
an axial direction ; consequently, the pitch is thirty-two 
times as much, or twenty-one feet and four inches. 

If measurements taken as successive divisions of the 
circumference give a successive increase of eight inches 
for each division, it shows that the propeller is a true 
screw with a pitch of twenty-one feet and four inches. 

It will be observed that the measurements made at one 
cleat in different positions of the straight-edge give deter- 
mination for the pitch at different points of the sstme helix, 
and therefore show whether the pitch varies from forward 
to after part of the blade. The measurements taken at 
different cleats, in successive positions of the straight-edge, 
show the pitch at corresponding points of different helices, 
and indicate whether the pitch varies from hub to peri- 
phery. 

The method here described is one of the simplest and 
most accurate that can be given for determining the pitch 
of a screw-propeller. The other measurements — the di- 
ameter of screw, length of blade, dimensions of hub, and 
fraction of pitch employed — are so simple as to need no 
explanation. 
24* 



282 



HAND-BOOK OF LAND AND MARINE ENGINES. 



HOW TO LINE UP A PROPELLER-SHAFT. 

Put two straight-edges on the slides, one at each end; 
run a line through their centre points, and continue it be- 
yond the shaft. Set a T square on one of the straight- 
edges, making one edge of the blade cut the centre point. 
Then erect a perpendicular, at the centre of the shaft to 
the line previously run, by looking it out of wind with the 
edge of the T square, or arranging it so that, when viewed 
from a distance, it covers the edge of the T square for the 
whole length. Then disconnect the crank from the rod, 
and swing it on the centre and half-centre, and measure 
the distances on its face and the two lines. If they vary 
at different points, the shaft is not in line, and must be ad- 
justed until the distances are the same from all points of 
the revolution. 




Radial Wheel. 

PADDLE-WHEELS. 

Paddle-wheels consist of two large wheels moving on 
the end of the engine-shaft. They are made by attaching 
arms to the centres on the shaft and to two large rings, on 



HAND-BOOK OF LAND AND MARINE ENGINES. 283 

which are bolted the paddles or floats. As they are 
turned round, the resistance offered to them by the water 
causes the vessel to move, acting precisely on the same 
principle as a boat-oar ; by them the inertia of the water 
is made a means of locomotion. 

In using this appliance as a motive-power, its advan- 
tage greatly depends upon the amount of immersion. 
When the water approaches the centre, or reaches above, 
it is obvious the greatest waste of power will ensue. It is 
quite as obvious that the greater the diameter of the wheel 
the greater the leverage, and the greater is the effect 
obtained. There are various kinds of paddle-wheels, such 
as the ordinary radial, the cycloidal, and the feathering. 

The Ordinary Radial Wheel. — This wheel has the 
floats fixed on the radial arms. In this arrangement the 
floats enter the water with the whole of their faces pre- 
sented to it; the same action takes place as they come 
out. From this arises a great loss of power, for they 
should evidently offer the greatest resistance to the water 
when at their lowest point, and none when entering or 
leaving. From this cause, and the yielding of the water, 
the ship does not move as fast as the wheel. The loss is 
called slip, and is generally allowed to be from 10 to 20 
per cent. 

Cycloidal Wheels. — To obviate the difficulties and dis- 
advantages of the ordinary radial wheel, the cycloidal 
was advocated. Its peculiarity consists in dividing the 
float into two strips longitudinally. The strip farthest 
from the centre is behind the radius, and the other in front 
of it. The intention of this arrangement is, that the floats 
may meet the water with more uniformity. It is a very 
good form of wheel for large vessels. In order that the 
floats may enter and leave the water with the least possi- 
ble resistance, they should enter in a tangential direction 



284 



HAND-BOOK OF LAND AND MARINE ENGINES* 



to the curve which is being described by any point in the 
wheel. This is what is known as the cycloidal curve. 




Feathering Wheel. 

The Feathering Wheel. — In the feathering wheel the 
floats are governed by mechanism, which causes them to 
enter and leave the water in a position perpendicular to 
the direction of their motion. By this arrangement they 
offer the greatest resistance at the lowest point ; the floats 
are in fact at right angles to the surface of the water when 
immersed. 

In the feathering wheel, as each float is always perpen- 
dicular to the water, they progress with the same horizon- 
tal velocity, therefore the point of maximum resistance or 
centre of pressure must be in a line passing longitudinally 
along the centre of the float. But in the radial wheel 
this cannot be the case, for the outside edge of the float 
moves much faster than the inside ; the point where these 
two average each other is taken at a distance of one-third 
the depth of the board from the outer edge. 

Although the feathering wheel produces more useful 



HAND-BOOK OF LAND AND MARINE ENGINES. 



285 



effect with the same application of power than the radial 
wheel, there are many practical objections to its use, the 
most prominent of which are, the increased first cost, the 
excessive weight, and the frequent overhauling that they 
require. 

The Manley Paddle-Wheel. — This wheel has only five 
or six floats, each of which is secured to a rock-shaft, to 
which a crank is attached. The feathering mechanism is 
a frame eccentric to the main shaft, connected with each 
of the cranks by an arm. Each float is secured to the 
rock-shaft below the centre, so as to divide the pressure 
on the float equally between the feathering mechanism 
and the adjacent side frame of the wheel. It is the first 
machine for marine propulsion which, by its action' and 
application of power, has imitated the Indian's paddle, 
and has conformed to the first great principle necessary 
to be observed in propelling a vessel through the water, 
by obtaining the proper resistance for the power upon the 
water. 




Manley Paddle-Wheel. 



286 HAND-BOOK OF LAND AND MARINE ENGINES. 

This wheel does for the steam-ship what the Indian's 

paddle does for his boat, and even in greater perfection. 
It drops a paddle into undisturbed water, forces it back- 
ward or forward, as the case may be, in a direction exactly- 
perpendicular to the line of flotation, and, as it is being 
withdrawn from the water, another paddle is entering far 
ahead and grasping resistance entirely unused by the pre- 
ceding paddle. 

The operation is certain and constant while the power 
is applied. 

Immersion of Paddles. — The great difiiculty with 
paddle-wheels is to secure a proper immersion. As the 
ship proceeds on its voyage and consumes its store of coal, 
the vessel becomes lighter, and, consequently, its draught 
of water decreases. Therefore, supposing a paddle is 
properly immersed at the commencement of a voyage, it 
will be nearly out of the water at the end. At the com- 
mencement of a voyage the paddle must be too deeply 
immersed, at the middle the proper immersion will per- 
haps be attained, while there will be too little towards the 
end of the voyage. 

Disconnecting Paddle- Wheels. — In some instances, 
when the wind is fair and the ship is under canvas, the 
paddle-wheels are disconnected from the engine, and 
allowed to revolve on their bearings. Several contriv- 
ances, which it is unnecessary to mention here, have been 
introduced to accomplish this object. 

The paddle-shafty where it passes through the vessel's 
side, is usually surrounded with a lead stuffing-box, which 
will yield if the end of the shaft falls. This stufiing-box 
prevents leakage into the ship from the paddle-wheels ; but 
it is expedient, as a further precaution, to have a small 
tank on the ship's side a little below the stufiing-box, with 
a pipe leading down to the bilge, to catch and conduct 
away any water that may enter. 



HAND-BOOK OF LAND AND MARINE ENGINES. 287 

FLUID RESISTANCE. 

The scientific investigation of bodies in moving through 
a fluid is still involved in much obscurity, from the want 
of independent research on the part of the various authors 
who have undertaken the elucidation of the subject ; and 
the mistakes incidental to the researches of Newton, and 
other eminent philosophers, have overrun various depart- 
ments of physical science, and are now found most difficult 
of eradication. The circumstances in connection make it 
expedient to investigate the matter in a practical way, 
and to illustrate a few of the leading principles of 
mechanics which relate to this question. 

Mechanical power is pressure acting through space; 
and the amount of mechanical power developed by any 
combination is measurable by the amount of the pressure 
multiplied by the amount of space through which the 
pressure acts. A pressure of 10 pounds acting through a 
space of 1 foot represents the same amount of mechanical 
power as a pressure of 1 pound acting through a space of 
10 feet ; and 10 pounds gravitating through 1 foot, or 1 
pound gravitating through 10 feet, represent ten times 
the amount of mechanical power due to the gravitation of 
1 pound through 1 foot. 

In the same way, 1000 pounds gravitating through 1 
foot is equivalent to 1 pound gravitating through 1000 
feet, and, in general terms, the weight or pressure multi- 
plied by the space through which it acts represents the 
power universally. If, therefore, a body falls freely 
through space by the operation of gravity, since it parts 
with none of its power during its descent, the whole power 
must be accumulated in the falling body in the shape of 
momentum; and, at the instant of reaching the ground, 
the body must have such an amount of mechanical power 



288 HAND-BOOK OF LAND AND MARINE ENGINES. 

stored up in it, as would suffice to carry it up again to the 
position from which it fell, if the power were directed to 
the accomplishment of that object. 

The amount of mechanical power, therefore, in any 
moving body, is measurable by the weight of the body 
multiplied by the space through which it must have fallen 
by gravity, to acquire the velocity it possesses ; and this 
fundamental law, if distinctly apprehended, and kept con- 
stantly in recollection, will insure exemption from the 
fallacies which prevail so generally among authors in ref- 
erence to such subjects. In Newton's " Second Law of 
Motion," it is» maintained that "the change or alteration 
of motion, produced in a body by the action of any 
external force, is always proportional to that force," from 
whence it is inferred, that to produce twice the quantity 
of motion in a body, will require just twice the power; 
and this is the doctrine maintained by Kobinson in his 
" Mechanical Philosophy," and by Hutton, Gregory, and 
most other English authors who have undertaken to illus- 
trate such questions. 

Nevertheless, there is no doubt whatever that this doc- 
trine, is altogether erroneous, as was shown by Leibnitz at 
the time of its promulgation, and subsequently by Smea- 
ton, who, by a series of carefully executed experiments, 
proved very clearly that, to double the velocity of a moving 
body, it required four times the amount of mechanical 
power that was necessary to put it into motion at first ; 
and consequently, that the momentum of moving bodies 
of the same weight varies as the squares of their respective 
velocities. ^ 

The soundness of this conclusion is made manifest by 
a reference to the law of falling bodies, by which it will 
be found that it is necessary a body should fall through 
four times the height to double its ultimate speed ; nine 



HAND-BOOK OF LAND AND MARINE ENGINES. 289 

times the height, to treble its ultimate speed, and so on ; 
showing that the height, and therefore the power exerted 
in creating the motion, must be as the square of the ulti- 
mate speed ; and consequently, that the ultimate velocities 
of all falling bodies will be as the square roots of the 
heights from which they have respectively descended. In 
the case of two bodies of equal weight, therefore, moving 
in space, but of which one moves with twice the velocity 
of the other, the faster will have four times the amount 
of mechanical power stored up in it that is possessed by 
the slower ; for it must have fallen from four times the 
height, to acquire its doubled velocity ; and the relative 
quantities of powier capable of being exerted by bodies of 
the same weight are measurable in all cases by the spaces 
through which the weight or pressure acts. 

A cannon-ball moving with a velocity of 2000 feet a 
second, has four times the momentum of a cannon-ball of 
equal weight movj^ng with a velocity of 1000 feet a 
second ; and every particle of a stream of water moving 
with a velocity of 10 miles an hour has four times the 
momentum of every particle of a stream of water with a 
velocity of five miles an hour. Every particle of the 
faster stream, therefore, will exert four times the efiect in 
impelling any body on which it impinges, that is exerted 
by every particle of the slower stream. But in the faster 
stream not only will every particle impinge with four times 
the force, but there will be twice the number of particles 
impinging in a given time, and a quadrupled force for each 
particle ; and twice the number of particles striking in a 
given time gives an effect eight times greater, in a given 
time, with a doubled velocity of the stream. 

Accordingly, it is found that in a water- or wind-mill, 
when the velocity of the current is doubled, the power ex- 
erted is about eight times greater than before ; and it is 
25 T 



290 HAND-BOOK OF LAND AND MARINE ENGINES. 

also found that a steam-vessel, to realize a double velocity, 
requires about eight times the amount of power. But these 
results, it is obvious, have reference, not merely to the in- 
creased velocity of the particles of matter, but to the 
large number of them brought into operation ; and any 
given quantity of water, if flowing with a doubled velocity, 
would only exert four times the power exerted before. In 
the same manner, a steam-vessel, to accomplish any given 
voyage in half the time, would require four times the 
quantity of coal previously consumed ; for although eight 
times the quantity of coal would be consumed per hour, 
yet only half the number of hours would be occupied in 
accomplishing the distance. 

The number of particles of water to be displaced by a 
vessel in performing any given voyage is the same, what- 
ever the velocity of the vessel may be ; but the number 
of particles displaced in the hour differs with every dif- 
ferent velocity, and the power expended must consequently 
vary in a corresponding proportion. It may, hence, be 
asserted generally, that the power or dimension of an engine 
necessary to propel a vessel increases nearly as the cube of 
the velocity required to be attained ; but the consumption 
of fuel will only increase in about the ratio of the square 
of the velocity, looking to the number of miles of distance 
actually performed by a steamship. 

In order to be able to calculate the absolute amount of 
power required to produce a given effect, it is necessary to 
be acquainted with the laws which govern the resistance 
of fluids to the motion of solid bodies in them, which are 
generally admitted to be based on the following theorem. 
If a plain surface move at a given velocity through a 
fluid at rest, in a direction perpendicular to itself, the re- 
sistance is proportional to the density of the fluid, and to 
the square of the velocity of the plane. 



HAND-BOOK OF LAND AND MARINE ENGINES. 291 

SIGNIFICATION OF SIGNS USED IN CALCULATIONS. 



= signifies Equality, 


• as 3 added to 2 = 5. 


+ " 


Addition, 


"4 + 2 = 6. 


— " 


Subtraction, 


" 7 — 4 = 3. 


X " 


Multiplication, 


" 6 X 2 = 12. 


-T- " 


Division, 


" 16 ~- 4 = 4. 


I 11 I 


Proportion, 


" 2 is to 3, so is 4 to 6. 


s/ " 


Square Root, 


" n/ = 4. 


y/ " 


Cube Root, 


" 4^64 = 4. 


32 u 


3 is to be squared, " 3^ = 9. 


33 « 


3 is to be cubed, 


" 3^ = 27. 


2 + 5x4= 28^signifie3 


that two, three, or more num- 




bers are 


to be taken together, as 2 + 5 




= 7, and 4 times 7 = 28. 


V5' — 


3^ = 4 signifies 


that 3 squared taken from 5 




squared. 


and the square root extracted 




= 4. 





v'lO X 6 = 1*587 signifies that where 10 is multiplied by 
15 6 and divided by ^15, the cube root of 

the quotient = 1*587. 

DECIMAL. 

Decimal Apithmetic is of Hindoo origin, and was 
introduced into Arabia about one thousand years ago, 
from whence it spread throughout Europe and the entire 
civilized world. The base, 10, originated from the ten 
fingers, which were used for counting before characters 
were formed to denote numbers. The base, 10, admits of 
only one binary division, which gives the prime number 5 
without fraction. The trinary divisions give an endless 
number of decimals. 

Decimal Fractions are fractions in which the denomina- 
tor is a unit or 1 with ciphers annexed, in which case 



292 



HAND-BOOK OF LAND AND MARINE ENGINES. 



they are commonly expressed by writing the numerator 
only with a point before it, by which it is separated from 
whole numbers ; thus, '5, which denotes five-tenths, j% ; 
•25, that is, j%%. 

DECIMAL EQUIVALENTS OF INCHES, FEET, AND 

YAKDS. 



Fractions 

of 
an Inch. 



I ■ 

1 inch- 



Decimals 
of an 
Inch. 

•0625 : 
•125 
•1875 : 
•25 

•3125 : 
•375 
•4375 : 
•5 

•5625 : 
•625 
•6875 : 
•75 

•8125 : 
•875 
•9375 : 
1-00 



Decimals 
of a 
Foot. 

•00521 
•01041 
•01562 
•02083 
•02604 
•03125 
•03645 
•04166 
•04688 
•05208 
•05729 
•06250 
•06771 
•07291 
•07812 
•08333 



Inch. 


Feet. 




Yards. 


1 = 


-0833 


= 


■0277 


2 = 


•1666 


= 


•0555 


3 = 


•25 


= 


•0833 


4 = 


•3333 


=z 


•nil 


5 = 


•4166 


= 


•1389 


6 = 


•5 


= 


•1666 


7 = 


•5833 


— 


•1944 


8 = 


•6666 


=• 


•2222 


9 = 


•75 


= 


•25 


10 = 


•8333 


— 


•2778 


11 = 


•9166 


= 


•3055 


12 :rrr 


1-000 


= 


•3333 



DECIMAL EQUIVALENTS OF POUNDS AND OUNCES. 
Oz. 

i 

1* 



2i 



Lbs. 
•015625 
•03125 
•046875 
•0625 
•09375 
•125 
•15625 



Oz. Lbs. 

3 ^1875 
31 -21875 

4 -25 
41 -28125 

5 ^3125 
51 ^34375 

6 -373 



Oz. Lbs. 
61 ^40625 

7 
71 



-4375 
•46875 

8^ -5 

81 ^53125 



•5625 
•59375 



Oz. 


Lbs. . 


10 


•625 


lOi 


•65625 


11 


•6875 


^H 


•71876 


12 


•75 


12i 


•78125 


13 


•8125 



Oz. 


Lbs. 


m 


-84375 


u 


•875 


^H 


•90625 


15 


•9375 


15J 


•96875 


16 


I- 



USEFUL NUMBEKS IN CALCULATING WEIGHTS AND 
MEASUKES, ETC. 

Feet multiplied by .00019 equals miles. 

Yards ' ** -0006 ** miles. 

Links " -22 « yards. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



293 



Links multiplied by -66 e 


qual 


.8 feet. 


Feet 


(( 


1-5 


<( 


links. 


Square inches 


(( 


•007 


(( 


square feet. 


Circular inches 


<c 


•00546 


<( 


square feet. 


Square feet 


<( 


•111 


i( 


square yards. 


Acres 


a 


•4840 


(I 


square yards. 


Square yards 


n 


•0002066 


^i 


acres. 


Width in chains 


(( 


•8 


tt 


acres per m. 


Cube feet 


(( 


•04 


tt 


"L^e yards. 


Cube inches 


it 


•00058 


n 


cube feet. 


U. S. bushels 


n 


•0495 


it 


cube yards.. 


U. S, bushels 


tc 


1-2446 


tt 


cube feet. 


U. S. bushels 


it 


2150-42 


ti 


cube inches. 


Cube feet 


c< 


•8036 


<< 


U, S. bushels. 


Cube inches 


<( 


•000466 


(< 


U. S. bushels. 


U. S. gallons 


i( 


•13367 


n 


cube feet. 


U. S. gallons 


t( 


•231 


<< 


cube inches. 


Cube feet 


it 


7^48 


a 


U. S. gallons. 


Cylindrical feet 


i( 


5-874 


tt 


U. S. gallons. 


Cube inches 


<( 


•004329 


a 


U. S. gallons. 


Cylindrical inches 


« 


•0034 


a 


U. S. gallons. 


Pounds 


<( 


•009 


ti 


cwt. 


Pounds 


tc 


•00045 


tt 


tons. 


Cubic foot of water 


tl 


62-5 


ti 


lbs. avoird. 


Cubic inch of water 


ti 


•03617 


it 


lbs. avoird. 


Cylindrical foot of water 


n 


49-1 


a 


lbs. avoird. 


Cylindrical inch of water 


ft 


•02842 


a 


lbs. avoird. 


U. S. gallons of water 


(( 


13-44 


tl 


1 cwt. 


U. S. gallons of water 


'< 


268-8 


if 


1 ton. 


Cubic feet of water 


iC 


1'^ 


tt 


1 cwt. 


Cubic feet of water 


iC 


35-88 


it 


1 ton. 


Cylindrical foot of water 


(I 


6- 


it 


U. S. gallons. 


Column of water, 12 in. high, 1 


in. diameter 


tl 


341 lbs. 


183-346 circular inches 






ti 


1 square foot, 


2200 cylindrical inches 






it 


1 cubic foot. 


French metres multiplied by 8*281 


It 


feet. 


Kilogrammes 


it 


2-205 


tl 


avoird. lbs. 


Grammes 


a 


•002205 


tt 


avoird. lbs. 


25* 











294 



HAND-BOOK OF LAND AN^ MARINE ENGINES. 



DECIMAL EQUIVALENTS TO THE FRACTIONAL PARTS 
OF A GALLON OR AN INCH. 

(The Inch or Gallon being divided into 32 parts.) 

(In multiplying decimals, it is usual to drop all but the first two or three figures.) 



1 

a 


o 


3 
1 


-2 




a 


o 

O 


O 
12 


a 
3 


1 


1 

a 

1 


o 

o a 

O 


5 
23 


c 
51 


3 

a 
21 


•03125 


1-32 


•375 


3-8 


•71875 


23-32 


•0625 


1-16 


2 


i 


i 


•40625 


13-32 


13 


3i 


H 


•75 


3-4 


24 


6 


3 


•09375 


3-32 


3 


1 


^ 


•4375 


7-16 


14 


Si 


11 


•78125 


25-32 


25 


6i 


3i 


•125 


1-8 


4 


1 


^ 


•46875 


15-32 


15 


31 


11 


•8125 


13-16 


26 


6i 


3i 


•15625 


5-32 


5 


u 


§ 


•5 


i 


16 


4 


2 


•84375 


27-32 


27 


61 


31 


•1875 


.VI 6 


6 


H 


1 


•53125 


17-32 


17 


4i 


2i 


•875 


7-8 


28 


7 


3i 


•21875 


7--32 


7 


11 


i 


•5625 


9-16 


18 


4^ 


2i 


•90625 


29-32 


29 


7i 


3§ 


•25 


1-4 


8 


2- 


1 


•59375 


19-32 


19 


41 


21 


•9375 


15-16 


30 


7i 


31 


•281251 9-32 


9 


2i 


U 


•625 


5-8 


20 


5 


2^ 


•96875 


31-32 


31 


71 


3i 


•3125 


5-16 


10 


2i 


u 


•65625 


21-32 


21 


5i 


21 


1^000 


1 


32 


8 


4 


•34375 


11-32 


11 


!i 


11 


•6875 


11-16 


22 


5i 


21 













UNITS. 

Unit of Heat. — The unit of heat varies : the French unit 
of heat, called a " caloric,"^ is the amount of heat necessary 
to raise one kilogramme (2*2046215 pounds) of water one 
degree Centigrade, or from 0° C. to 1° C. In this country 
and in England the amount of heat necessary to raise one 
pound of water one degree Fahrenheit, or from 32° Fah. 
to 33° Fah., is taken as the unit of heat. 

Unit of Length. — The unit of length used in this 
country and in England is the yard, the length of which 
has been determined by means of a pendulum, vibrating 
seconds in the latitude of London, in a vacuum and at 
the level of the sea. The length of such a pendulum is 
to be divided into 3,913,929 parts, and 3,600,000 of these 
parts are to constitute a yard. The yard is divided into 
36 inches, so that the length of the seconds pendulum in 
London is 39*13929 inches. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



295 



The French unit of length, called the m^tre, has been 
taken as being the ten-millionth part of the quadrant of 
a meridian passing through Paris ; that is to say, the ten- 
millionth part of the distance between the equator and the 
pole, measured through Paris. It is equal to 39'3707898 
inches. The metre is divided into one thousand milli- 
metres, one hundred centimetres, and ten decimetres; 
while a decametre is ten metres ; a hectometre one hun- 
dred metres, a kilometre one thousand metres, and a myri- 
ametre ten thousand metres. The following table gives 
the value of these measurements in English inches and 
yards : 



Millimetre... 
Centimetre... 
Decimetre... 

Metre 

Decametre -. 
Hectometre.. 
Kilometre... 
Myriametre 



In English Inches. 


In English Yards. 


0-03937 


0-0010936 


0-39371 


0-0109363 


3-93708 


0-1093633 


39-37079 


1-0936331 


393-70790 


10-9363310 


3937-07900 


109-3633100 


39370-79000 


1093-6331000 


393707-90000 


10936-3310000 



One English yard is equal to 0-91438 metre ; while one 
mile is equal to 1*60931 kilometres. 

Unit of Surface. — For the unit of surface, the square 
inch, foot, and yard adopted in this country and in Eng- 
land are replaced in the metric system by the square 
millimetre, centimetre, decimetre, and metre. 

1 square m^tre = 1-1960333 square yards. 
1 square inch = 6*4513669 square centimetres. 
1 square foot = 9*2899683 square decimetres. 
1 square yard = 0*83609715 square metre. 

Unit of Capacity. — The cubic inch, foot, and yard 
furnish measures of capacity; but irregular measures, 
such as the pint and gallon, are also used in this country 



296 



HAND-BOOK OF LAND AND MARINE ENGINES^ 



and in England. The gallon contains ten pounds avoir- 
dupois weight of distilled water at 62° Fah. ; the pint is 
one-eighth part of a gallon. 

The French unit of capacity is the cubic decimetre or 
litre, equal to 17607 English pints, or 0*2200 English 
gallon ; and we have cubic inches, decimetres, centimetres, 
and millimetres. 

1 litre = 61-027052 cubic inches. 

1 cubic foot = 28-315311 litres. 
1 cubic inch = 16386175 cubic centimetres. 
1 gallon = 4-543457 litres. 

Unit of Weight. — The unit of weight used in this 
country and in England — the pound — is derived from 
the standard gallon, which contains 277-274 cubic inches ; 
the weight of one-tenth of this is the pound avoirdupois, 
which is divided into 7000 grains. 

The French measures of weight are derived at once from 
the measures of capacity, by taking the weight of cubic 
millimetres, centimetres, decimetres, or metres of water at 
its maximum density, that is at 4° C. or 39° Fah. A cubic 
metre of water is a tonne, a cubic decimetre a kilogramme, 
a cubic centimetre a gramme, and a cubic millimetre 
a milligramme. 



Milligramme (xoVxr P^^t of a gramme). 
Centigramme (yJo part of a gramme).. 
Decigramme {^q part of a gramme).... 

Gramme 

Decagramme (10 grammes) 

Hectogramme (100 grammes) 

Kilogramme (1000 grammes) 

Mjriagramme (10000 grammes) 



In English 
Grains. 



0-015432 

0-154323 

1-543235 

15-432349 

154-323488 

1543-324880 

15432-348800 

154323-488000 



In Pounds 
Avoirdupois 
1 pound = 
700 grammes. 



0-0000022 
0-0000220 
0-0002205 
0-0022046 
0-0220462 
0-2204621 
2-2046213 
22-0462126 



Unit of Time op Duration. — The unit of time or dura- 



HAND-BOOK OF LAND AND MARINE ENGINES. 297 

tion is the same for all civilized countries. The twenty- 
fourth part of a mean solar day is called an hour, and 
this contains sixty minutes, each of which is divided into 
sixty seconds. The second is universally used as the unit 
of duration. 

Another unit of time is the period occupied by the 
earth in making one revolution around the sun, in refer- 
ence to an assumed fixed star, which unit is called a side- 
real year, and contains 365 days, 6 hours, 9 minutes, and 
9*6 seconds mean solar time. 

Unit of Velocity. — The units of velocity adopted by 
difierent scientific writers vary somewhat; the most usual, 
perhaps, in regard to sound, falling bodies, projectiles, etc., 
is the velocity of feet or metres per second. In the case 
of light and electricity, miles and kilometres per second 
are employed. 

Unit of Work- — In this country and in England the 
unit of work is usually the foot-pound, viz., the force 
necessary to raise one pound weight one foot above the 
earth in opposition to the force of gravity. A horse-power 
is equal to 33,000 pounds raised to a height of one foot in 
one minute of time. 

In France the kilogrammetre is the unit of work, and 
is the force necessary to raise one kilogramme to a height 
of one metre against the force of gravity. One kilogram- 
metre = 7*233 foot-pounds. The cheval-vapeur is nearly 
equal to the English horse-power, and is equivalent to 
32,500 pounds raised to a height of one foot in one minute 
of time. The force competent to produce a velocity of 
one m^tre in one second, in a mass of one gramme, is 
sometimes adopted as a unit of force. 

Unit of Pressure. — The pressure of the atmosphere at 
the level of the ocean, with the barometer at 30 inches, is 
taken as the unit in estimating and comparing pressures 
and elastic forces. 



298 HAND-BOOK OF LAND AND MAEINE ENGINES. 

THEORY OF THE STEAM-ENGINE. 



WATER. 



AIR. THERMOMETERS. ELASTIC FLUIDS. 



CALORIC, 



HEAT. COMBUSTION. GASES. 



STEAM. 



HAND-BOOK OP LAND AND MARINE ENGINES. 299 

WATER. 

The Composition of Water.— Pure water is composed 
of the two gases, hydrogen and oxygen, in the proportions 
of 2 measures of hydrogen to 1 of oxygen, or, 1 weight of 
hydrogen to 8 of oxygen ; or, oxygen 89 parts by weight, 
and by measure 1 part, hydrogen, by weight, 11 parts, and 
by measure 2 parts. 

Pure water in nature does not exist, nor is it to be found 
in the laboratory of the chemist. Fortunately, however, 
it happens that pure water is not necessary, or even desir- 
able, for household or manufactviring purposes. The 
presence of air or other gases adds greatly to the ease with 
which steam may be generated ; the ammonia that is 
present in most water improves it for manufacturing 
purposes, and it has been abundantly proved that the 
salts which are present in most well-waters add greatly 
to their wholesomeness. 

But at the same time it must be remembered that some 
waters contain impurities which render them unfit for use. 
Of these various impurities, the insoluble portion is in 
general the least injurious, though it is frequently the 
most oflTensive. 

Water swarming with minute animalcules, or turbid 
with the clay and sand that have been stirred up from the 
bed of some stream, may be offensive though it is not 
dangerous ; while, on the other hand, water may be beauti- 
fully clear to the eye and not very offensive to the taste, 
and yet hold in solution the most deadly poison, in the 
form of dissolved salts or the soluble portions of animal 
excreta. 

It also happens that these insoluble matters are easily 
and cheaply removed, while the utmost care is required to 
free water from matter which exists in a dissolved state. 



300 HAI^D-BOOK OF LAND AKD MARINE ENGINES. 




NAYLOR'S VERTICAL ENGINE. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



301 



The specific gravity of all waters is not the same. 
The following table will show the specific gravity of 
different seas. 



Water from the Dead Sea... 


Weight of 

water being 

1000. 


Weight of an 
imperial gal- 
lon in pounds. 


1240 
1029 
1028 
1015 


12.4 
10.3 
10.2 
10.2 


*' *' <* Mediterranean 


" << *< Irish Channel 


" " ** Baltic Sea 





Fop the production of steam, all waters are not equal. 
Water holding salt in solution, earth, sand or mud in sus- 
pension, requires a higher temperature to produce steam 
of the same elastic force than that generated from pure 
water. 

Water, like all other fluids and gases, expands with 
heat and contracts with cold down to 40'^ Fah. 

If water be boiled in an open vessel it is impossible to 
raise the temperature above 212° Fah., as all the surplus 
heat which may be applied passes off with the steam. 

If heat be applied to the top of a vessel, ebullition will 
not take place, as very little heat would be communicated 
to other parts of the vessel, and the water would not boil. 

Ebullition, or boiling of water or other liquids, is 
effected by the communication of heat through the sepa- 
ration of their particles. 

The evaporation of water is the conversion of water as 
a liquid into steam as a vapor. 

Latent Heat of Water or Ice. — If a pound of ice at 
32"^ Fah. be mixed with a pound of water at 111°, the 
water will gradually dissolve the ice, being just sufficient 
for that purpose, and the residuum will be two pounds of 
water 32° Fah. 
26 



302 HAND-BOOK OF LAND AND MARINE ENGINES. 

The 79 units of heat which are apparently lost having 
been employed in performing a certain amount of work, 
i. e.^ in melting the ice or separating the molecules and 
giving them another shape, and as all work requires a 
supply of heat to do it, these 79 units have been consumed 
in performing the work necessary to melt the ice. 

Latent Heat of Water. — If the pound of water were 
reconverted into ice, it would have to give up the 79 units 
of latent heat. Hence we see why it should be called 
the latent heat of water and not the latent heat of ice. 

Suppose that we have a pound of ice, at a temperature 
of 32^ Fah., and that we mix it with a pound of water at 
212^, the ice will be melted and we shall have two pounds 
of water at a temperature of 51°. 

Now, if we take a pound of ice at a temperature of 32° 
and mix it with a pound of water at 212°, the resulting 
mixture of the two pounds will have a temperature of 122°. 
Hence we see that the ice, in melting, has absorbed enough 
heat to raise two pounds of water through a temperature 
of 122° — 51°= 71°, or one pound through 142°, and we 
say that the latent heat of the liquefaction of water is 
142°. 

The latent heat of the evaporation of water can be 
determined in a similar manner by condensing a pound 
of steam at 212° Fah. with a given weight of water at a 
known temperature, and also by mixing a pound of water 
at a temperature of 212° Fah. with the same amount of 
water as was employed in the case of steam, and observ- 
ing the difference of temperature of the resulting mixtures. 

Thus, a pound of water at 212° mixed with ten pounds 

at 60° gives eleven pounds at 74°. A pound of steam at 

212° mixed with ten pounds of water at 60° gives eleven 

pounds of w^ter at 162°. In other words, the steam on 

* i. e., that is. 



HAND-BOOK OF LAND AND MARINE ENGINES. 303 

being condensed has given out heat (which was not previ- 
ously sensible to the thermometer) enough to raise eleven 
pounds of water through a temperature of 162° less 74° 
equals 88°, or one pound through 968°, and we say that the 
latent heat of the evaporation of water is 968°. 

If a pound of mercury and a pound of water be heated 
to the same temperature, and allowed to cool, it will be 
found that the mercury cools 30 times as fast as the water; 
hence we say that the specific heat of mercury is about 
one-thirtieth that of water. 

The boiling-point of water is that temperature at which 
the tension of its vapor exactly balances the pressure of 
the atmosphere. But the temperature at which the ebul- 
lition of water begins depends upon the elasticity of the 
air or other pressure. 

At the level of the sea, the barometer standing at 29*905 
(or nearly 30) inches of mercury, water will boil at 212° 
Fah. ; but the higher we ascend above the level of the 
sea, the more the boiling-point diminishes. 

Water attains its greatest density at 39° Fah., or 7° 
above freezing. 

Although it is claimed that water presses in every di- 
rection and finds ij:s level, water can be compressed y^^ 
of an inch in every 18 feet by each atmosphere or press- 
ure of 15 pounds to the square inch of pressure applied ; 
but when the pressure is removed, its elasticity restores it 
to its original bulk. 

Water becomes solid and crystallized as ice owing to 
the abstracting of its heat. 

The force of expansion exerted by water in the act of 
freezing has been found irresistible in all mechanical ex- 
periments to prevent it. 

Water in a vacuum boils at about 98° Fah., and as- 
sumes a solid at 32 degrees in the atmosphere, when it 
expands ^^^ its original bulk. 



304 HAND-BOOK OF LAND AND MARINE ENGINES. 

Water, after being long kept boiling, affords an ice 
more solid, and with fewer air-bubbles, than that which is 
formed from unboiled water. 

Pure water, kept for a long time in vacuo, and after- 
wards frozen there, freezes much sooner than common 
water exposed to the same degree of cold in the open at- 
mosphere. 

Ice formed of water thus divested of its air, is much 
more hard, solid, heavy, and transparent than common ice. 

Ice, after it is formed, continues to expand by decrease 
of temperature ; to which fact is probably attributable the 
occasional splitting and breaking up of the ice on ponds, 
etc. 

A cubic foot of water weighs 62} pounds ; a cubic foot 
of ice weighs 57*2 pounds. It follows that ice is nearly 
one-twelfth lighter than \|:ater. 

Now, if heat be applied to ice, the temperature of which 
is below freezing, the temperature will soon rise to 32"^ or 
freezing ; but any further application of heat cannot in- 
crease the temperature of the ice until the whole mass is 
melted. 

The specific gravity of ice is '92, and specific gravity of 
water is 1000 — water being the standard by which to 
obtain the specific gravity of all solids, fluids, and even 
gases. Though air is sometimes used as a standard for 
gases, water is more commonly used. 

The specific gravity of water is the comparative weight 
of a given bulk of water to the same bulk of any other 
liquid. Thus, if we take equal measures of the several 
different liquids, we shall find that they possess very dif- 
ferent weights. 

The weight of a pint of water, a pint of oil, and a pint 
of mercury will differ very materially. The mercUry will 
weigh 13 times more than water does, and the water will 
weigh a good deal more than the oil. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



305 





TABLE 








SHOWING THE 


WEIGHT 


OF WATER. 




1 


Cubic inch 


is equal 


to -03617 


pounds. 


12 


Cubic inches 


u 


•434 


a 


1 


Cubic foot 


a 


62-5 


u 


1 


Cubic foot 


u 


,7-50 


U. S. gallons 


1-8 


Cubic foot 


a 


112-00 


pounds. 


3584 


Cubic feet 


(I 


2240-00 


it 


1 ' 


Cylindrical inch 


(I 


•02842 


it 


12 


Cylindrical inches 


u 


•341 


u 


1 


Cylindrical foot 


« 


49-10 


u 


1 


Cylindrical foot 


ti 


6-00 


U. ft. gallons. 


2-282 


Cylindrical feet 


u 


112-00 


pounds. 


45-64 


Cylindrical feet 


u 


2240-00 


a 


11-2 


Imperial gallons 


u 


112-00- 


i( 


224-0 


Imperial gallons 


u 


2240-00 


u 


13-44 


U. S. gallons 


u 


112-00 


i( 


268-8 


U. S. gallons 


« 


2240-00 


a 



TABLE 

SHOWING THE WEIGHT OF WATER AT DIFFERENT TEMPERATURES. 



Temperature - 


Weight of a Cubic 


Temperature 


Weight of a Cubic 


Fahrenheit. 


Foot in Pounds. 


Fahrenheit. 


Foot in Pounds. 


40° 


62.408 


172° 


60.72 


42° 


62.406 


182° 


60.5 


52° 


62.377 


192° . 


60.28 


62° 


62.321 


202° 


60.05 


72° 


62.25 


212° 


59.82 


82° 


62.15 


230° 


59.37 


92° 


62.04 


250° 


58.85 


102° 


61.92 


275° 


58.17 


112° 


61.78 


300° 


57.42 


122° 


61.63 


350° 


55.94 


132° 


61.47 


400° 


54.34 


142° 


61.30 


450° 


52.70 


15-2° 


61.11 


500° 


51.02 


162° 


60.92 


600° 


47.64 



26^ 



U 



306 



HAND-BOOK OF LAND AND MARINE ENGINES. 



Water attains a minimum volume and a maximum den- 
sity at 40° Fah. ; any departure from that temperature in 
either direction is accompanied by expansion, so that 8° 
or 10° of l3old produce about the same amount of expan- 
sion as 8° or 10 '^ of heat. 

At 70° Fah., pure water will boil at 1° less of temper- 
ature, for an average of about 550 feet of elevation above 
sea-level, up to a height of one-half of a mile. At the 
height of 1 mile, 1° of boiling temperature will corres- 
pond to about 560 feet of elevation. 

The following table shows the approximate altitude 
above sea-level corresponding to different heights, or read- 
ings of the barometer ; and to the different degrees of Fah- 
renheit's thermometer, at which water boils in the open 
air. Thus, when the barometer, under undisturbed con- 
ditions of the atmosphere, stands at 24*08 inches, or when 
pure rain or distilled water boils at the temperature of 201° 
Fah., the place is about 5764 feet above the level of the 
sea, as shown by the table. 

TABLE 

SHOWJNG THE BOILING-POINT FOR FRESH WATER AT DIFFERENT 
ALTITUDES ABOVE SEA-LEVEL. 



Boiling- 


Altitude 


Boiling- 


Altitude 


Boiling- 


Altitude 


point in 


above sea- 


point in 
deg. Fah. 


above sea- 


point in 
deg. Fah. 


above sea- 


deg. Fah. 


level in feet. 


level in feet. 


level in feet. 


184° 


15221 


195° 


9031 


206° 


3115 


185° 


14649 


196° 


8481 


207° 


2589 


186° 


14075 


197° 


7932 


208° 


2063 


187° 


13498 


198° 


7381 


209° 


1539 


• 188° 


12934 


199° 


6843 


210° 


1025 


189° 


12367 


200° 


6304 


211° 


512 


190° 


11799 


201° 


5764 


212° 


sea- 1 ^ 
level/-" 


191° 


11243 


202° 


5225 




192° 


10685 


203° 


4697 






193° 


10127 


204° 


4169 


Below i 


?ea-level. 


194° 


9579 


205° 


3642 


213° 1 


511 



HAND-BOOK OF LAND AND MARINE ENGINES. 



307 



TABLE 

SHOWING THE WEIGHT OF WATER IN PIPE OF VARIOUS DIAM- 
ETERS 1 FOOT IN LENGTH. 



Diameter 


Weight 


Diameter 


Weight 


Diameter 


Weight 


in Inches. 


in Pounds. 


in Inches. 


in Pounds. 


in Inches. 


in Pounds. 


3 


3 


12i 


51 


22* 


172* 


3J 


3i 


12J 


53} 


23 


180} 


3i 


4J 


12f 


55* 


23* 


188} 


3| 


4f 


13 


57* 


24 


196} 


4 


5J 


13i 


59f 


24* 


204* 


41 


6i 


13J 


62} 


25 


213 


^ 


7 


13f 


64* 


25* 


222* 


4f 


7f 


14 


66f 


26 


230* 


5 


8^ 


14} 


69} 


26* 


239* 


5} 


9i 


m 


71* 


27 


248* 


5i 


10^ 


14| 


74} 


27* 


257| 


5f 


lU 


15 


76| 


28 


267} 


6 


m 


15} 


79} 


28* 


276J 


6i 


13i 


loj 


82 


29 


286j 


6J 


m 


15f 


84* 


29* 


296^ 


6| 


15| 


16 


874 


30 


306| 


7 


161 


161- 


90 


30* 


317} 


7i 


18 


16i 


92} 


31 


327* 


7i 


19i 


16| 


95* 


31* 


338} 


7f 


20J 


17 


98* 


32 


349 


8 


21f 


17} 


101* 


32* 


360 


8} 


23i 


17i 


104* 


33 


371} 


8^ 


24J 


17| 


107^ 


33* 


382* 


81 


26 


18 


110* 


34 


394 


9 


27J 


18} 


113^ 


34* 


405| 


9t 


29i 


m 


116* 


35 


417* 


9J 


30i 


18f 


1191 


35* 


429* 


9i 


32J 


19 


123 


36 


441| 


10 


34 


19} 


126} , 


36* 


454 


lOi 


35J 


19* 


129* ' 


37 


466* 


lOj 


37J 


19| 


132 


37* 


479} 


loi 


39i 


20 


136} 


38 


492} 


11 


41i 


20i 


1431 


SSh 


505} 


lU 


44t 


21 


150} 


39" 


518* 


lU 


45 


21* 


157* 


39* 


531i 


111 


47 


22 


165 


40 


545* 


12 


49 











308 HAND-BOOK OF LAND AND MARINE ENGINES. 




HASKIN'S VERTICAL HIGH-PRESSURE ENGINE. 



HAND-BOOK OF LAND AND MARINE ENGINES. 309 

AIR. J 

The atmosphere is known to extend at least 45 miles 
above the earth. 

Its composition is about 79 measures of nitrogen gas 
and 21 of oxygen ; or, in other words, air consists of, by- 
volume, oxygen 21 parts, nitrogen 79 parts ; by weight, 
oxygen 77 parts, nitrogen 23 parts. 

According to Dr. Prout, 100 cubic inches of air at the 
surface of the earth, when the barometer stands at 34 
inches, and at a temperature of 60° Fah., weighs about 
31 grains, being thus about 815 times lighter than water, 
and 11,065 times lighter than mercury. 

Since the air of the atmosphere is possessed of weight, 
it must be evident that a cubic foot of air at the surface 
of the earth has to support the weight of all the air di- 
rectly above it, and that, therefore, the higher we ascend 
up in the atmosphere the lighter will be the cubic foot of 
air ; or, in other words, the farther from the surface of the 
earth, the less will be the density of the air. 

At the height of three and a half miles it is known that 
the atmospheric air is' only half as dense as it is at the 
surface of the earth. 

From the nature of fluids, it follows that tte atmosphere 
presses against any body which comes in contact with it, 
because fluids exert a pressure in all directions — upwards, 
downwards, sidewise, and oblique. 

It is also known that the pressure on any point is equal 
to the weight of all the particles of the fluid in a perpen- 
dicular line between the point in contact and the surface 
of the fluid. 

The amount of pressure of a column of air whose base 
is one square foot, and altitude the height of the atmos- 
phere, has been found to be 2156 pounds avoirdupois, or 



310 HAND-BOOK OF LAND AND MARINE ENGINES. 

very nearly 15 pounds, of pressure on every square inch ; 
consequently, it is common to state the pressure of the at- 
mosphere as equal to 15 pounds on the square inch. 

If any gaseous body or vapor, such as steam, exerts a 
pressure equivalent to 15 pounds on the square inch, then 
the force of that vapor is said to be equal to one atmos- 
phere; if the vapor be equal to 30 pounds on every square 
inch, then it is equal to two atmospheres, and so on. Con- 
sequently, the atmospheric pressure is capable of support- 
ing about 30 inches of mercury, or a column of water 34 
feet high. 

It is also found that the pressure of the atmosphere is 
not constant even at the same place ; at the equator, the 
pressure is nearly constant, but is subject to greater 
change in the high latitudes. 

In some countries the pressure of the atmosphere varies 
so much as to support a column of mercury so low as 28 
inches, and at other times so high as 31, the mean being 
29*5, thus making the average pressure between 14 and 15 
pounds on the square inch. But in scientific books, gen- 
erally, the pressure is understood in round numbers to be 
15 pounds, so that a pressure exerted equal to 1, 2, 3, 4, 
etc., atmospheres, means such a pressure as would support 
30, 60, 90, 120, etc., inches of mercury in a perpendicular 
column, or 15, 30, 45, 60, etc., pounds on every square 
inch. 

Aip is a very slow conductor of heat, and is sometimes 
used as a non-conductor in hollow walls to prevent the 
radiation of heat. 

The pressure of the air differs at different latitudes ; 
for instance, at 7 miles above the surface of the earth the 
air is 4 times lighter than it is at the earth's surface ; at 14 
miles it is 16 times lighter, and at 21 miles it is 64 times 
lio-hter. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



311 



Under a pressure of 5 J tons to the square inch, air be- 
comes as dense, and would weigh as much per cubic foot, 
as water. 

The greatest heat of air in the sun is about 140° Fah., 
and it probably never exceeds 145^ Fah. 

Aip, like all other gases, expands but one volume for 
each 493° of temperature through which it is raised, and 
in order to double its volume, we must raise it 493° more, 
which will bring it to a temperature of 986° Fah. 

It requires 13,817 cubic feet of air to make one pound. 
One cubic foot of air at the surface of the earth weighs 
527 grains, or i ounce avoirdupois. 

Although the atmosphere may extend to the height of 
45 miles, yet its lower half is so compressed as to occupy 
only 3i miles, so greatly do the upper portions expand when 
relieved from pressure. Hence, at the height of 3} miles, 
the elasticity of the atmosphere is J ; at 7 miles, i; at 10 i 
miles, I ; at 14 miles -p^g, etc. 



TABLE 

SHOWING THE WEIGHT OF THE ATMOSPHERi; IN POUNDS, AVOIR- 
DUPOIS, ON ONE SQUARE INCH, CORRESPONDING WITH DIFFERENT 
HEIGHTS OF THE BAROMETER, FROM 28 INCHES TO 31 INCHES, 
VARYING BY TENTHS OF AN INCH. 



Barometer 


Atmosphere 


Barometer 


Atmosphere 


Barometer 


Atmosphere 


in Inches. 


in Pounds. 


in Inches. 


in Pounds. 


in Inches. 


in Pounds. 


28.0 


13.72 


29.1 


14.26 


30.1 


14.75 


28.1 


13.77 


29.2 


14.31 


30.2 


14 80 


28.2 


13.82 


' 29.3 


14.36 


30.3 


14.85 


28.3 


13.87 


29.4 


14.41 


30.4 


14.90 


28.4 


13.92 


29.5 


14.46 


30.5 


14.95 


28.5 


13.97 


29.6 


14.51 


30.6 


15.00 


28.6 


14.02 


29.7 


14.56 


30.7 


15.05 


28.7 


14.07 


29.8 


14.61 


30.8 


15.10 


28.8 


14.12 


29.9 


14.66 


30.9 


15.15 


28.9 


14.17 


30.0 


14.70 


31.0 


15.19 


29.0 


14.21 











312 HAND-BOOK OF LAND AND MARINE ENGINES. 

TABLE 

SHOWING THE EXPANSION OF AIR BY HEAT, AND TIJE INCREASE 
IN BULK IN PROPORTION TO INCREASE OF TEMPERATURE. 



Fahrenheit. 




Bulk. 


Fahrenheit. 




Bulk. 


Temp. 


82 


Freezing-point. 


1000 


Temp. 


Id 


Temperate 


1099 


<< 


33 


'* 


1002 


'< 


76 


Summer heat. 


. 1101 


(( 


31 


it 


1004 


(( 


77 




1104 


a 


35 


it 


1007 


(( 


78 




1106 


li 


30 


tt 


1009 


tt 


79 




1108 


«' 


37 


*i 


1012 


ti 


80 




1110 


(( 


38 


a 


1015 


it 


81 




1112 


ti 


39 


a 


1018 


" 


82 




1114 


a 


40 


It 


1021 


(( 


83 




1116 


»' 


41 


ii 


1023 


it 


84 




1118 


a 


42 


tt 


1025 


It 


85 




1121 


a 


43 


ti 


1027 


it 


86 




1123 


ti 


44 


tt 


1030 


it 


87 




1125 


a 


45 


tt 


1032 


it 


88 




1128 


u 


46 


tt 


1034 


a 


89 




1130 


(( 


47 


ti 


1036 


it 


90 




1132 


i< 


48 


it 


1038 


it 


91 




1134 


<( 


49 


tt 


1040 


ti 


92 




1136 


(( 


50 


tt 


1048 


it 


98 




1138 


ii 


51 


ti 


1045 


a 


94 




1140 


a 


52 


ti 


1047 


it 


95 




1142 


n 


53 


it 


1050 


ti 


96 Blood heat 


1144 


a 


54 


it 


1052 


ti 


97 


ti 


1146 


ti 


55 


it 


1055 


tt 


98 


It 


1148 


it 


56 


Temperate... 


1057 


ti 


99 


it 


1150 


it 


57 


(( 


1059 


ti 


100 


it 


1152 


a 


58 


(( 


1062 


ti 


110 


Fever heat 112 1173 


ti 


59 


(( 


1064 


" 


120 


(( 


1194 


ti 


60 


(( 


1066 


(( 


130 


it 


1215 


ti 


61 


ti 


1069 


(< 


140 


tt 


1235 


it 


62 


ti 


1071 


(( 


150 


it 


1255 


" 


63 


ti 


1073 


4( 


160 


' it 


1275 


(( 


64 


ti 


1075 


it 


170 


Spirits boil 17 


6 1295 


(i 


65 


it 


1077 


il 


180 


tt 


1315 


<' 


66 


ti 


1080 


<' 


190 


it 


1334 


(( 


67 


ti 


1082 


(( 


200 


it 


1364 


(( 


68 


tt 


1084 


(( 


210 


it 


1372 


(( 


69 


it 


1087 


(< 


212 


Water boils 


1375 


it 


70 


tt 


1089 


'' 


302 


(( 


1558 


it 


71 


it 


1091 


it 


392 


it 


1739 


it 


72 


It 


1093 


ti 


482 


a 


1919 


ti 


73 


ti 


1095 


tt 


572 


44 


2098 


ti 


74 


ti 


1097 


ti 


680 


44 


2312 



HAND-BOOK OF LAND AND MARINE ENGINES. 818 

THE THERMOMETER. 

The Thermometep is an instrument for measuriug vari- 
ations of heat or temperature. The principle upon which 
thermometers are constructed, is the change of volume 
which takes place in bodies, when their temperature 
undergoes an alteration. Generally speaking, all bodies 
expand when heated, and contract when cooled, and in 
such a manner that under the same circumstances of 
temperature they return to the same dimensions. 

The properties of mercury, which render it preferable 
to all other liquids (unless for particular purposes), are 
these: 1. It supports, before it boils and is reduced to 
vapor, more heat than any other fluid, and endures a 
greater cold than would congeal most other liquids. 2. It 
takes the temperature of the medium in which it is placed 
more quickly than any other fluid. Count Rumford found 
that mercury was heated from the freezing- to the boiling- 
point of water in 58 seconds, while water took 133 seconds, 
and air 617 seconds, the heat applied being the same in 
all the three cases. 3. The variations of its volume, within 
limits, which include the temperatures most frequently re- 
quired to be observed, are found to be perfectly regular 
' and proportional to the variations of temperature. 

The Mercurial Thermometer consists of a bulb and 
stem of glass of uniform bore. A sufficient quantity of 
mercury having been introduced, it is boiled to expel the 
air and moisture, and the tube is then hermetically 
sealed. 

The standard points are ascertained by immersing the 
thermometer in melting ice, and in the steam of water 
boiling under the pressure of 14*7 pounds on the square 
inch, and marking the positions of the top of the column ; 
the interval between those points is divided into the proper 
27 



314 



HAND-BOOK OF LAND AND MARINE ENGINES. 



COMPAEATIVE SCALE OF CENTIGRADE, FAHREN- 
HEIT, AND REAUMER THERMOMETERS. 



.£P 



Boiling-point 100 - 
of water. 

90 - 

80 - 

70 

60 - 

50 

40 

30 

20 

10 

Freezing-point. - 

10 

20 

30 - 

Mercury freezes. 40 



I 
212 



— 




— 


200 


190 
180 




170 


— 


160 


150 
140 
130 


— 


120 


110 


100 


90 


80 


70 




60 


— 


50 


40 


— 


30 


— 




20 


10 


ZERO 
10 


20 


30 
40 





80 Boiling-point 
of water. 

- 70 

- 60 

- 50 

- 40 

- 30 

- 20 

- 10 

- Freezing-point. 

- 10 

- 20 

- 30 

- 40 



HAND-BOOK OF LAND AND MARINE ENGINES. 315 

number of degrees — 100 for the Centigrade scale ; 180 
for Fahrenheit's ; and 80 for Reaumer's. 

The pate of expansion of mercury with rise of tempera- 
ture increases as the temperature becomes higher ; from 
which it follows, that if a thermometer showing the dila- 
tation of mercury simply were made to agree with an air 
thermometer at 32° and 211"^, the mercurial thermometer 
would show lower temperatures than the air thermometer 
between those standard points and higher temperatures 
beyond them. 

In Fahrenheit's time it was supposed that the greatest 
degree of cold attainable was reached by mixing snow 
and common salt, or snow and sal-ammoniac. A ther- 
mometer plunged into a mixture of this kind was found 
to fall much below the point indicated by melting ice. 
The point to which the mercury fell by contraction, when 
plunged in this mixture, Fahrenheit marked 0, the in- 
terval between this and the freezing-point he divided into 
thirty-two equal divisions, hence the freezing-point came 
to be indicated by 32°. 

Then equal divisions were continued upwards, and the 
mercury, by expansion, reaching 212,° when the thermome- 
ter was immersed in boiling water, this 212° was called 
the boiling-point. This is briefly the reason for Fahren- 
heit adopting his method of division, and why he has 212° 
— 32° = 180° between the freezing- and the boiling-points. 

But a much lower temperature than Fahrenheit's 0° has 
been observed in cold countries, and as mercury becomes 
solid at 40° Fah. below freezing, it would be the most 
accurate limit to the scale, as it would register the utmost 
extremes of heat and cold to which the mercurial ther- 
mometer is sensible. , 

Centigrade Thermometep. — On the scale of this 
thermometer the space between the freezing- and the boil- 



316 HAND-BOOK OF LAND AND MARINE ENGINES. 

ing-points of water is divided into 100 equal parts, the 
zero point being placed at freezing. This division being 
in harmony with our decimal arithmetic, is better adapted 
than Fahrenheit's or Eeaumer's scale for scientific pur- 
poses. 

Reaumer's Thepmometep. — In Reaumer's thermometer 
the melting-point of ice is taken as zero, and the distance 
between that and the boiling-point for water is divided 
into 80 equal parts. Reaumer having observed that 
between those temperatures spirits of wine (which he used 
for the therm ometric fluid) expanded from 1000 to 1080 
parts. This division soon became general in France and 
other countries, and a great number of valuable observa- 
tions have been recorded in terms of it; but it is now 
seldom used in works of science. 

Change of Zepo. — There is a circumstance connected 
with the mercurial thermometer which requires to be 
attended to, when very exact determinations of tempera- 
ture are to be made, as it has been observed that when 
thermometers which have been constructed for several 
years are placed in melting ice, the mercury stands in 
general higher than the zero point of the scale ; and this 
circumstance, which renders the scale inaccurate, has been 
usually ascribed to the slowness with which the glass of 
the bulb acquires its permanent arrangement, after having 
been heated to a high degree in boiling the mercury. 

In very nice experiments it is always necessary to verify 
the zero point ; for it was found that when thermometers 
have been kept during a certain time in a low temperature, 
the zero point rises, but falls when they have been kept in 
a high temperature, and this remark applies equally to 
old thermometers and to those which have been recently 
constructed. 

Absolute Zero. — Absolute zero is a temperature which 



HAKD-BOOK OF LAND AND MARINE ENGINES. 317 

is fixed by reasoning, although no opportunity ever occurs 
for observing it. It is the temperature corresponding to 
the disappearance of gaseous elasticity, or, in other words, 
that point at which gas would become a solid, as when 
water becomes ice. This temperature is called, in reference 
to all gases, the absolute zero. The positions of the ab- 
solute zero on the ordinary scales would be 

On Reaumur's scale 219-2° below 0°. 
On Centigrade scale 274° " " 
On Fahrenheit's scale 461*2° " " 

Register Thermometeps. — In meteorological observa- 
tions, it is of great importance to ascertain the limits of 
the range of the thermometer in a given period of time, or 
during the absence of the observant. Numerous contriv- 
ances have accordingly been proposed for this purpose ; 
but Six's is the most frequently used. It consists of a long 
cylindrical bulb, with a tube bent in the form of a siphon 
and terminating in a small cavity ; a part of the tube is 
filled with mercury, but the bulb and the remaining por- 
tion of the tube and the cavity are filled with highly recti- 
fied alcohol. 

The use of the mercury in the middle of the tube is to 
give motion to two indices, which consist each of a small 
glass tube in which a small bit of iron-wire is enclosed, the 
end being capped with enamel. 

The indices are of such a size that they freely move 
within the tube and allow the spirits to pass, but a slender 
spring attached to each presses against the side of the 
tube, and prevents the index from falling down when it has 
been raised to any point, and the mercury recedes. 

But this instrument has all the defects which belong to 
the spirit thermometer, and the indications are in some 
degree deranged by the expansion and contraction of the 
27* 



318 HAND-BOOK OF LAND AND MARINE ENGINES. 

enclosed column of mercury, and, probably, also by the 
friction of the indices. 

Spirit Thermometers are used to measure temperatures 
at and below the freezing-point of mercury. Their devia- 
tions from the air thermometer are greater than those of 
the mercurial thermometer. 

Solid Thermometers. — Solid thermometers are some- 
times used, which indicate temperatures by showing the 
difference between the expansions of a pair of bars of two 
substances whose rates of expansion are diiferent. When 
such thermometers are used to indicate temperatures higher 
than the boiling-point of mercury under one atmosphere 
(about 676° Fah.), they are called Pyrometers. 

Fixed Temperatures are the boiling-point for water 
and the melting-point for ice. 

Underground Temperatures. — The following table 
shows the increase of temperature in degrees Fahrenheit, 
below the surface of the earth, corresponding to depth, etc. 



Feet. 


Deg. Fah. 


Feet. 


Deg. Fah. 


68 


47-9 


1,290 


58-3 


299 


48-8 


1,414 


59-4 


621 


50-7 


1,652 


61-2 


939 


57-8 


1,900 


61-4 



Rules jor comparing Degrees of Temperature indicated 
by different Thermometers, — Rule I. — Multiply degrees of 
Centigrade by 9, and divide by 5 ; or multiply degrees of 
Eeaumur by 9, and divide by 4. Add 32 to the quotient 
in either case, and the sum is degrees of Fahrenheit. 

Rule II. — From degrees of Fahrenheit subtract 32; 
multiply the remainder by 5, and divide by 9 for degrees 
of Centigrade; or multiply by 4, and divide by 9 for de- 
grees of Reaumur. 



HAND-BOOK OF LAND AND MARINE ENGINES, 319 




WILLIAMS' THREE-CYUNDER ENGINE. 



320 HAND-BOOK OF LAND AND MARINE ENGINES. 

ELASTIC FLUmS. 

Elastic fluids are divided into two classes — permanent 
gases and vapors. The gases cannot be converted into 
the liquid state by any known process of art ; whereas the 
vapors are readily reduced to the liquid form by pressure 
or diminution of temperature. In respect of their mechan- 
ical properties there is, however, no essential difference 
between the two classes. 

Elastic fluids, in a state of equilibrium, are subject to 
the action of two forces ; namely, gravity, and a molecular 
force acting from particle to particle. 

Gravity acts on the gases in the same manner as on all 
other material substances ; but the action of the molecular 
forces is altogether different from that which takes place 
among the elementary particles of solids and liquids ; for, 
in the case of solid bodies, the molecules strongly attract 
each other (hence results their cohesion), and, in the case 
of liquids, exert a feeble or, evanescent attraction, so as to 
be indifferent to internal motion ; but, in the case of the 
gases, the molecular forces are repulsive, and the molecules 
yielding to the action of these forces, tend incessantly to 
recede from each other, and, in fact, do recede until their 
further separation is prevented by an exterior obstacle. 

Thus, air confined within a close vessel exerts a constant 
pressure against the interior surface, which is not sensible, 
, only because it is balanced by the equal pressure of the 
atmosphere on the exterior surface. This pressure exerted 
by the air against the sides of a vessel within which it is 
confined, is called its elasticity, elastic force, or tension. 

Conditions of Equilibrium. — In order that all the parts 
of an elastic fluid may be in equilibrium, one condition 
only is necessary; namely, that the elastic force be the 
same at every point situated in the same horizontal plane. 



HAND-BOOK OF LAND AND MARINE ENGINES. 321 

This condition is likewise necessary to the equilibrium of 
liquids, and the same circumstances give rise to it in both 
cases ; namely, the mobility of the particles, and the action 
of gravity upon them. 

The density of bodies being inversely as their volumes, 
the law of Mariotte may be otherwise expressed by saying 
the density of an elastic fluid is directly proportional to 
the pressure it sustains. Under the pressure of a single 
atmosphere, the density of air is about the 770th part of 
that of water ; whence it follows that, under the pressure 
of 770 atmospheres, air is as dense as water. 

The average atmospheric pressure being thus equal to 
that of a column of water of about 32 feet in altitude at 
the bottom of the sea, at a depth of 24,640 (equals 770 
multiplied by 32) feet, or 4| miles, air would be heavier 
than water ; and though it should still remain in a gaseous 
state, it would be incapable of rising to the surface. 

CALORIC. 

The ordinary application of the word heat implies the 
sensation experienced on touching a body hotter, or of a 
higher temperature ; whilst the term calorie provides for 
the expression of every conceivable existence of temper- 
ature. 

Caloric is usually treated as if it were a material sub- 
stance ; but, like light and electricity, its true nature has 
yet to be determined. 

Caloric passes through different bodies with different 
degrees of velocity. This has led to the division of bodies 
into eonductors and non-eonduetors of caloric ; the former 
includes such bodies as metals, which allow caloric to 
pass freely through their substance, and the latter com- 
prises those that do not give an easy passage to it, such as 
stones, glass, wood, charcoal, etc. 

V 



322 HAND-BOOK OF LAND AND MARINE ENGINES. 

Radiation of Caloric. — When heated bodies are ex- 
posed to the air, they lose portions of their heat by projec- 
tions in right lines into space from all parts of their 
surface. Radiation is effected by the nature of the surface 
of the body ; thus, black and rough surfaces radiate and 
absorb more heat than light and polished surfaces. Bodies 
which radiate heat best, absorb it best. 

Reflection of caloric differs from radiation, as the 
caloric is in this case reflected from the surface without 
entering the substance of the body. Hence, the body 
which radiates, and consequently absorbs most caloric, 
reflects the least, and vice versa. 

Latent caloric is that which is insensible to the touch, 
or incapable of being detected by the thermometer. The 
quantity of heat necessary to enable ice to assume the fluid 
state, is equal to that which would raise the temperature 
of the same weight of water 140° Fah., and an equal 
quantity of heat is set free from water when it assumes 
the solid form. 

Sensible caloric is free and uncombined, passing from 
one substance to another, affecting the senses, in its passage, 
determining the height of the thermometer, and giving 
rise to all the results which are attributed to this active 
principle. 

Evaporation produces cold, because caloric must be 
absorbed in the formation of vapor, a large quantity of 
it passing from a sensible to a latent state, the capacity for 
heat of the vapor formed being greater than that of the 
fluid from which it proceeds. 

Caloric is, therefore, either free and sensible, or latent 
and insensible. Caloric is known to be the cause of fluidity ; 
and the absence of caloric, the cause of solidity. If heat 
be applied to ice or iron, it becomes fluid ; if exposed to 
cold, it resumes its solid form. 



HAND-BOOK OF LAND AND MARINE ENGINES. 323 

The theory is, that all solid bodies are composed of par- 
ticles of matter held together by the attraction of cohesion ; 
but that a portion of caloric is interposed between these 
particles, so that they do not ever actually touch — though 
appearing to ; that when more caloric is applied, the par- 
ticles are separated by it, or to receive it, which causes an 
expansion, as all bodies do expand by heat; that when, by - 
a further application of caloric, the particles, to receive it, 
have separated so far asunder as sufficiently to weaken the 
attraction of cohesion, the body ceases to be solid, and 
passes into the fluid state, in which the particles move 
freely among one another. 

HEAT. 

It would be difficult to over-estimate the importance of 
the part played by heat, both on a grand scale in the 
laboratory of nature, and on a minor scale, in the domain 
of human art and science. In the former respect, it is not 
only an essential condition to the existence of life on this 
planet, but also the prime agent in putting in motion most 
of the physical changes which take place at the earth's 
surface. 

In the latter, it must be regarded not only as furnishing 
man with the chief means he possesses of imitating nature, 
and moulding and modifying natural productions to his 
wants; but also as bestowing on him the ability to gen- 
erate and apply at pleasure a force equally stupendous 
and easy to control. 

Heat is one form of mechanical power, or, more prop- 
erly, a given quantity of heat is the equivalent of a de- 
terminate amount of mechanical power; and as heat is 
capable of producing power, so, contrariwise, power is 
capable of producing heat. 



324 HAND-BOOK OF LAND AND MARINE ENGINES. 




7 f 

Roper's Caloric Engine. 

As it becomes necessary to have a standard for measur- 
ing the amount of heat absorbed or evolved during any 
operation, in this country the standard unit is the amount 
of heat necessary to raise the temperature of a pound of 
water V Fah., or from 32° to 33° Fah. 

Specific Heat.— Diiferent bodies require very different 
quantities of heat to effect in them the same change of 
temperature. The capacity of a body for heat is termed 
its " specific heat," and may be defined as the number of 
units of heat necessary to raise the temperature of 1 pound 
of that body 1° Fah. 

When a substance is heated it expands, and its tempera- 
ture is increased. It is evident, therefore, that heat is 



HAND-BOOK OF LAND AKD MARINE ENGINES. 



325 




Section of Roper's Caloric Engine. 

required both to raise the temperature and to increase the 
distance between the particles of the substance. 

The heat used in the latter case is converted into inte- 
rior work, and is not sensible to the thermometer; but it 
will be given out, if the temperature of the substance is 
reduced to the original point. 

Thus, while heat is apparently lost, it is only stored up, 
ready to do work, and the substance possesses a certain 
amount of potential energy, or possibility of doing work. 

Now, as different substances vary greatly in their molec- 
ular constitution, expanding and contracting the same 
amount with widely differing degrees of force, it is to be 
expected that the quantity of heat that will raise one sub- 
stance to a given temperature may produce a less or 
greater degree of sensible heat to another ; and we find in 
practice that such is the case. 
28 



326 HAKD-BOOK OF LAND AND MARINE ENGINES. 

The condition of heat is measured as a quantity, and its 
amounts in different bodies and under different circum- 
stances are compared by means of the changes in some 
measurable phenomenon produced by its transfer or dis- 
appearance. 

In so using changes of temperature, it is not to be taken 
for granted that equal differences of temperature in the 
same body correspond to equal quantities of heat. This 
is the case, indeed, for perfectly gaseous bodies ; but that 
is a fact only known by experiment. 

On bodies in other conditions, equal differences of tem- 
perature do not exactly correspond to equal quantities of 
heat. To ascertain, therefore, by an experiment on the 
changes of temperature of any given substances, what pro- 
portion two quantities of heat bear to each other, the only 
method which is of itself sufficient, in the absence of all 
other experimental data, is the comparison of the weights 
of that substance which are raised from the same low tem- 
perature to a high or fixed temperature. 

The Unit of Heat. — The unit of heat, or thermal unit 
employed, is the quantity of heat, as before stated, that 
would raise 1 pound of pure water 1° Fah., or from 39° to 
40° Fah. 

The reason for selecting that part of the scale which is 
nearest the temperature of the greatest density of water, 
is because the quantity of heat corresponding to an inter- 
val of one degree in a given weight of water is not exactly 
the same in different parts of the scale of temperature. 

Latent Heat. — Latent heat means a quantity of heat 
which has disappeared, having been employed to produce 
some change other than elevation of temperature. By 
exactly reversing that change, the quantity of heat which 
had disappeared is reproduced. 

When a body is said to possess or contain so much 
latent heat, what is meant is simply this : that the body is 



HAND-BOOK OF LAND AND MARINE ENGINES. 327 

in a condition into which it was brought from a former 
different condition by transferring to it a quantity of heat 
which did not raise its temperature, the change of con- 
dition having been different from change of temperature, 
and that by restoring the body to its original condition in 
such a manner as exactly to reverse the former process, 
the quantity of heat formerly expended can be reproduced 
in the body and transferred to other bodies. 

When a body passes from the solid to the liquid state, 
its temperature remains stationary, or nearly so, at a cer- 
tain melting point, during the whole operation of melting, 
and in order to make that operation go on, a quantity of 
heat must be transferred to the substance melted, having a 
certain amount for each unit of weight of the substance. 
That heat does not raise the temperature of the substance, 
but disappears in causing its condition to change from the 
solid to the liquid state. 

When a substance passes from the liquid to the solid 
state, its temperature remains stationary, or nearly so, dur- 
ing the whole operation of freezing ; a quantity of heat 
equal to the latent heat of fusion is produced in the body, 
and in order that the operation of freezing may go on, that 
heat must be transferred from that body to some other 
substance. 

Sensible Heat. — Sensible heat is that which is sensible 
to the touch or measurable by the thermometer. 

Mechanical Equivalent of Heat. — The mechanical equiv- 
alent of heat is the amount of work performed by the 
conversion of one unit of heat into work. This has been 
determined to be equal in amount to the work required to 
raise 772 pounds one foot high, or one pound 772 feet 
high. And as heat and work are mutually convertible, if 
a body weighing one pound, after falling through a height 
of 772 feet, were to have its motion suddenly arrested, it 



328 HAND-BOOK OF LAND AND MARINE ENGINES. 

would develop sufficient heat to raise the temperature of a 
pound of water one degree. 

If a pound of water, at a temperature of 212^ Fah., is 
converted into steam, the latter will have a volume of 
about 27 i cubic feet. Now, suppose that the water is 
evaporated in a long cylinder of exactly one foot cross 
section, open to the atmosphere at the top. When all the 
water in the cylinder has disappeared, there will be a 
column of steam 274 feet high, which has risen to this 
height against the pressure of the atmosphere. 

The pressure of the air being nearly 15 pounds per 
square inch, the pressure per square foot is 2115 pounds ; 
and the external work performed by the water, in chang- 
ing into steam, will be an amount required to raise 2115 
pounds to a height of 27 i feet, or about 57,644 foot- 
pounds. 

Now, since 772 foot-pounds of work require one unit of 
heat, the external Avork will take up 57,644 divided by 
772, equals 74*64 units of heat. 

But it has been shown that the total number of units of 
heat required to change water into steam is about 968 
(more accurately, 966*6). Hence the internal work will 
be equal to an amount developed by the conversion of 
966*6 less 74*67, equals 891*93 units of heat into work, 
and this will equal 891*93, multiplied by 772 equals 
688,569 foot-pounds. 

Mechanical Theory of Heat. — The mechanical theory 
of heat is now generally adopted. It considers that heat 
and work are interchangeable, and on this theory can be 
explained what becomes of the latent heat. All solid 
bodies are supposed to be made up of molecules, which 
are not in contact, but are prevented from separating by 
a force called cohesion. 

If a body i^ heated to a sufficient temperature, the force 



HAND-BOOK OF LAND AND MARINE ENGINES. 829 

of expansion becomes equal to that of cohesion, and the 
body is liquefied ; and if still more heat is applied, the 
force of expansion exceeds that of cohesion, and the liquid 
becomes a vapor. 

But in each of these changes work is performed, and 
the heat that is supplied is converted into work. 

For instance, if ice is at a temperature of 32^, and heat 
is applied, this is converted into the work that is developed 
in changing the ice into water, and we say that heat 
becomes latent, and when water is at 212°, and we con- 
tinue to apply heat ; this is converted into the work that 
must be done in changing the water into steam. 

Dynamic Equivalent of Heat. — It is a matter of 
ordinary observation that heat, by expanding bodies, is 
a source of mechanical energy ; and conversely, that me- 
chanical energy, being expended either in compressing 
bodies or in friction, is a source of heat. 

In all other cases in which heat is produced by the 
expenditure of mechanical energy, or mechanical energy 
by the expenditure of heat, some other change is produced 
besides that which is principally considered; and this 
prevents the heat and the mechanical energy from being 
exactly equivalent. 

Power of Expansion by Heat. — When bodies expand, 
the molecules of which they are composed are pushed 
farther asunder by the oscillatory motion communicated 
to them. The heat may be described as entering the sub- 
stance and immediately setting to work to separate the 
particles. The power or energy it exerts to do this is 
immense. 

Molecular or Atomic Force of Heat. — All molecules 

are under the influence of two opposite forces. The one, 

molecular attraction, tends to bring them together; the 

other, heat, tends to separate them; its intensity varies 

28* 



330 HAND-BOOK OF LAND AND MARINE ENGINES. 

with its velocity of vibration. Molecular attraction is 
only exerted at infinitely small distances, and is known 
under the name of cohesion, affinity, and adhesion. 

Total OP Actual Heat. — If, when a substance, by the ex- 
penditure of energy in friction, is brought from a condi-' 
tion of total privation of heat to any particular condition 
of heat, we subtract from the total energy so expended, 
first, the mechanical work performed by the action of the 
substance on external bodies, through changes of its vol- 
ume, during such heating ; secondly, the mechanical work 
due to mutual actions between the particles of the sub- 
stance itself during such heating, the remainder will rep- 
resent the energy which is employed in making the sub- 
stance hot. 

Communication of Heat. — Heat may be communicated 
from a hot body to a cold one in three ways, — .by radia- 
tion, conduction, and circulation. 

The rapidity with which heat radiates varies, other 
things being equal, as the square of the temperature of 
the hot body in excess of the temperature of the cold one ; 
so that a body, if made twice as hot, will lose a degree of 
temperature in one-fourth of the time; if made three 
times as hot, it will lose a degree of temperature in one- 
ninth of the time, and so on in all other proportions. 

Transmission of Heat. — Tredgold and others have 
made experiments to ascertain the rate at which heat is 
transferred from metal to gases and from gases to metal. 
Other things being equal, it has been found that the rate 
of transference is as the difierence of temperature. But in 
practice the conditions are difierent from those in the ex- 
periment; generally, in experiments, the air has been still, 
and the gases moving under natural draught; but in loco- 
motive practice, the velocity of the gases is so great as to 
render the results of most experiments inapplicable. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



331 



Effects of Heat on the Circulation of Water in Boilers. 

— As the particles of water rise heated from the bottom 
of the boiler, other particles necessarily subside into their 
places, and it is a point of considerable importance to 
• ascertain the direction in which the currents approach the 
plate to receive heat. A particle of water cannot leave 
the heated plate until there is another particle at hand to 
occupy its position ; and, therefore, unless a due succession 
in the particles is provided for, the plate cannot get rid 
of its heat, and the proper formation of steam is hindered. 

But it must be understood that vaporizing does not 
depend on the quantity of heat applied to the plate, but 
on the quantity of heat abstracted from it by the particles 
of water. 

Medium Heat. — The medium heat of the globe is placed 
at 50° ; at the torrid zone, 75° ; at moderate climates, 50° ; 
near the Polar regions, 36° Fah. 

The extremes of natural heat are from 70° to 120° ; of 
artificial heat, 91° to 36000° Fah. 



LATENT HEAT OF VARIOUS SUBSTANCES. 



Ice 


Fah. 
140** 


Steam 

Vinegar 


Fah. 

990° 

875 


Sulphur 

Lead. 


144 

162 


Ammonia 

Alcohol 

Ether 


860 

442 

301 


Beeswax 

Zinc 


176 

493 



TABLE OF THE RADIATING POWER OF DIFFERENT 
BODIES. 



Water 100 

Lamp-black 100 

Writing-paper 100 

Glass 90 

India-ink 88 

Bright lead 19 

Silver 12 



Blackened tin 100 

Clean *' 12 

Scraped ** 16 

Ice 85 

Mercury 20 

Polished iron 15 

Copper 12 



332 



HAND-BOOK OF LAND AKD MARINE ENGINES. 



TABLE 

SHOWING THE EFFECTS OF HEAT UPON DIFFERENT BODIES. 



Fah. 
Cast-iron, thoroughly '^ oi^ao 

smelted / "^'^^ 

Fine gold melts 1983 

Fine silver "■ 1850 

Copper '* 2160 

Brass *< 1900 

Red heat, visible by day 1077 
Iron red-hot in twi- ^ qq. 

light / 

Common fire 790 

Iron, bright red in \ ^r^ 

the dark / '^^ 

Zinc melts 740 

Quicksilver boils.... 630 

Linseed oil 600 



Fah. 

Lead melts 594° 

Bismuth ** 476 

Tin " 421 

Tin and Bismuth, ^ ooo 

equal parts, melt... j 
Tin, 3 parts. Bismuth \ 

5, and Lead 2 parts, y 212 

melt J 

Alcohol boils 174 

Ether " 98 

Human blood (heat of) 98 

Strong wine freezes 20 

Brandy '' 7 

Mercury melts 39 



COMBUSTION. 

Combustion is, strictly speaking, the development of 
heat by chemical combination ; but though this may take 
place from the union of a variety of bodies, the om- 
nipresent agent, oxygen, plays so vastly more important a 
part than all others in the disengagement of light and 
heat, that the act of its combination with other bodies is 
pre-eminently entitled combustion. 

Since combustion, in the ordinary acceptation of the 
word, is the only means had recourse to in the arts for the 
development of artificial heat, perfect combustion may, for 
our purpose, be defined to be — the combination of a com- 
bustible body with the largest measure of oxygen with 
which it is capable of uniting. In fact, for all practi- 
cal purposes, the fuel, or combustible body, employed may 
be regarded as composed exclusively of carbon and hydro- 
gen; so that our inquiry becomes narrowed to the combi- 
nations of oxygen with these two elementary substances. 



HAND-BOOK OF LAKD AND MARINE ENGINES. 333 




334 HAND-BOOK OF LAND AND MARINE ENGINES. 

No substance in nature is combustible of itself, to what- 
ever degree of heat it may be exposed ; nor can it be ignited 
only when in presence of or in mechanical mixture with 
air, or its vital element, oxygen, because combustion is con- 
tinuous ignition, and can only be made to exist by main- 
taining in the combustible mixture the heat necessary to 
ignite it. 

Chemical combination, in every case, is accompanied 
by a production of heat ; every decomposition, by a disap- 
pearance of heat equal in amount to that which is produced 
by the combination of the elements which are to be sepa- 
rated. 

When a complex chemical action takes place in which 
various combinations and decompositions occur simulta- 
' neously, the heat obtained is the excess of the heat pro- 
duced by the combinations above the heat, which disap- 
pears in consequence of the decompositions. 

Sometimes the heat produced is subject to a further de- 
duction, on account of heat which disappears in melting 
or evaporating some of the substances which combine 
either before or during the act of combination. 

Substances combine chemically in certain proportions 
only. To each of the substances known in chemistry, a cer- 
tain number can be assigned, called its chemical equivalent, 
having these properties: — 1st. That the proportions by 
weight in which substances combine chemically can all be 
expressed by their chemical equivalents, or by simple mul- 
tiples of their chemical equivalents. 2d. That the chemi- 
cal equivalent of a compound is the sum of the chemical 
equivalents of its constituents. 

Chemical equivalents are sometimes called atomic 
weights or atoms, in accordance with the hypothesis that 
they are proportionate to the weights of the supposed 
atoms of bodies, or smallest similar parts into which bodies 



J 
HAND-BOOK OF LAND AND MARINE ENGINES. 335 

are assumed to be divisible by known forces. The term 
atom is convenient from its shortness, and can be used to 
mean *' chemical equivalent/' without necessarily affirming 
or denying the hypothesis from which it is derived, and 
which, how probable soever it may be, is, like other molec- 
ular hypotheses, incapable of absolute proof. 

The chief elementary combustible constituents of ordi- 
nary fuel are carbon and hydrogen. Sulphur is another 
combustible constituent of ordinary fuel, but its quantity 
is small and its heating power of no practical value. 

Coal is composed, so far as combustion is concerned, of 
solid carbon and a gas consisting of hydrogen and carbon. 

When the coal is heated, it first discharges its gas ; the 
solid carbon left then ignites in presence of oxygen, and 
will retain the temperature necessary to combustion so long 
as oxygen is applied. 

The Ingredients of Fuel. — Fixed or free carbon which 
is left in the form of charcoal or coke after the volatile in- 
gredients of the fuel have been distilled away. This ingre- 
dient burns either wholly in the solid or partly in the 
solid or gaseous state ; the latter part being first dissolved 
by previously formed carbonic acid, as already explained. 

Hydrocarbons, such as gas, pitch, tar, naphtha, etc., 
all of which must pass into the gaseous state before being 
burned. If mixed on their first issuing from among the 
burning carbon with a large quantity of air, these in- 
flammable gases are completely burned, with a transparent 
blue flame, producing carbonic acid and steam. 

Mixture of Fuel and Air. — In burning charcoal, coke, 
and coals with a small proportion only of hydrocarbons, a 
supply of air sufficient for complete combustion will enter 
from the ash-pit through the bars of the grate, provided 
there is a sufficient draught, and that care is taken to dis- 
tribute the fresh fuel evenly over the fire, and in moderate 
quantities at a time. 



336 



HAND-BOOK OF LAND AND MARINE ENGINES. 



Available Heat of Combustion. — The available heat 
of combustion of one pound of a given sort of fuel is that 
part of the total heat of combustion which is communicated 
to the body, to heat which the fuel is burned. 

Anthracite Coal. — The chemical composition of an- 
thracite coal is similar to charcoal, from which it differs 
chiefly in its form, being very hard and compact, and in 
the greater quantity of ashes which it contains. It is, like 
charcoal, unaltered in form after exposure to the strongest 
heat; even after passing through a blast furnace it has 
equally as sharp edges, and is in form exactly as it was 
before. 

COMPOSITION OF DIFFEKENT KINDS OF ANTHKA- 
CITE COAL. 



Lehigh Coal...., 
Schuylkill Coal 

Pottsville 

Pinegrove 

Wilkesbarre 

Carbondale , 



88.50 
92.07 
94.10 
79.67 
88.90 
90.23 






7.50 
5.03 
1.40 
7.15 
7.68 
7.07 



4.00 
2.90 
4.50 
3.28 
3.49 
2.70 



« 03 

9. 2 



L57 
1.50 
1.54 
1.40 
1.40 



The analysis of anthracite shows good coal of that class 
to be composed of 90*45 carbon, 2*43 hydrogen, 2*45 oxy- 
gen, some nitrogen, and 4*67 ashes. 

The ashes generally consist, like those of bituminous 
coal, of silex, alumina, oxide of iron, and chlorides, which 
generally evaporate and condense on cold objects in the 
form of white films. 

Anthracite is not so inlBiammable as either dry wood or 
bituminous coal, but it may be made to burn quite as 
vividly as either, by exposing it to a strong draught, or in 
a large mass to the action of the air. 



HAND-BOOK OF LAND AND MARINE ENGINES. 8C7 

The Quantity of Air required for the Combustion of 
Anthracite Coal. — In view of the quantity of oxygen 
required to unite chemically with the various constituents 
of the coal, we find that in 100 pounds of anthracite coal, 
consisting of 91 per cent, of carbon and 9 per cent, of the 
other matter, it will be necessary to have 243*84 pounds of 
oxygen, since to saturate a pound of carbon by the forma- 
tion of carbonic acid requires 2| pounds of oxygen. To 
saturate a pound of hydrogen in the formation of water 
requires 8 pounds of oxygen ; hence 3*46 pounds of hydro- 
gen will take 27'68 pounds of oxygen for its saturation. 

If then we add 243*84 pounds of oxygen for its satura- 
tion, 271*52 pounds of oxygen are required for the com- 
bustion of 100 pounds of coal. 

A given weight of air contains nearly 23*32 per cent, 
of oxygen ; hence to obtain 271*52 pounds of oxygen, we 
must have about four times that quantity of atmospheric 
air, or, more accurately, 1164 pounds of air for the combus- 
tion of 100 pounds of coal. 

A cubic foot of air at ordinary temperatures weighs 
about '075 pound ; so that 100 pounds of coal require 
15,524 cubic feet of air, or one pound of coal requires 
about 155 cubic feet of air, supposing every atom of the 
oxygen to enter into combination. 

If, then, from one-third to one-half of the air passes 
unconsumed though the fire, an allowance of 240 cubic 
feet of air for each pound of coal will be a small enough 
allowance to answer the requirements of practice, and in 
some cases as much as 320 cubic feet will be required. 

The Evaporative Efficiency of a Pound of Anthracite 
Coal. — The evaporative efficiency of a pound of carbon 
has been found, experimentally, to be equivalent to that 
necessary to raise 14,000 pounds of water through one de- 
gree, or 14 pounds of water through 1000 degrees, sup- 
29 W 



338 



HAND-BOOK OF LAND AND MARINE ENGINES. 



posing the whole heat generated to be absorbed by the 
water. 

Now, if the water be raised into steam from a temper- 
ature of 60°, then 1118*9° of heat will have to be im- 
parted to it to convert it into steam of 15 pounds pressure 
per square inch; 14,000 divided by 1118*9 equals 12*5 
pounds will be the number of pounds of water, therefore, 
which a pound of carbon can raise into steam of 15 pounds 
pressure from a temperature of 60°. This, however, is a 
considerably larger result than can be expected in practice. 

Bituminous Coal. — Under this class we range all that 
mineral coal which forms coke, that is, it swells upon 
being exposed to heat, burns with a bright flame, blazes, 
and after the flame disappears there remains a spongy, 
porous mass — coke — which burns without flame like 
charcoal. 

In its composition we find chiefly carbon, oxygen, hy- 
drogen, nitrogen, sulphur, and ashes, with a little water, 
which has been absorbed by the crevices. 

The following table shows the comparative composition 
of various sorts of mineral fuel : — 



Turf 


Carbon. 


Hydro- 
gen. 


Oxygen 

and 

Nitrogen. 


Ashes. 


58.09 
71.71 
82.92 
83.76 
87.95 
91.98 


5.93 

4.85 
6.49 
5.66 
5.24 
3.92 


31.37 

21.67 

10.86 

8.04 

5.41 

3.16 


4.61 
1.77 
0.13 
2.55 
1.40 
0.94 


Brown Coal 


Hard Bituminous Coal,.. 
Cannel Coal 


Cooking or Baking Coal- 
Anthracite 



An essential condition in forming coke is that the coal, 
on being heated, swells and changes into irregular, spongy 
masses, which adhere intimately together. This operation 
is designed to expel sulphur and hydrogen, and form a 



HAND-BOOK OF LAND AND MARINE ENGINES. 



339 



coal which is not altered by heat. The sulphur cannot be 
entirely separated from coke, or from carbon, no matter 
how high the heat may be ; neither can all the hydrogen 
be removed from carbon by simply heating the compound. 
If oxygen is admitted to these combinations, both sulphur 
and hydrogen may be almost entirely expelled, that is, 
provided the oxygen is not introduced under too high or 
too low a heat. 

The most important point, and one which has a direct 
bearing upon the value of coal, is the quantity of heat 
which it can evolve in combustion. 

If we assume that the quantity of ashes is equal in the 
four substances mentioned below, that is, 5 per cent, in 
each, and suppose further that pine charcoal furnishes 100 
parts of heat, the following table shows the quantity which 
must be liberated in their perfect combustion : 



Kind of Coal. 


Carbon. 


Hydro- 
gen. 


Water. 


Quantity 
of Heat. 


Brown Coal 


69 
75 
78 
85 
100 


3 
4 
4 
3 


23 
16 
13 

7 


78 
87 
90 ' 
94 
100 


Cooking Coal 


H (( 


Anthracite Coal 


Pure Carbon 





Bituminous coal, like all other fuel, is a compound sub- 
stance, which may be decomposed by heat into several dis- 
tinct elements — generally five or six, at least. So far as 
relates to combustion, we are concerned principally with 
but two of these, viz., solid carbon, represented by coke, 
and hydrogen, generally known under the indefinite term 
of ** gas." These two elements contain principally the 
full heating qualities of the coal. The carbon, so long as 
it remains as such, is always solid and visible. 

The hydrogen, when driven from the coal by heat, 



340 HAND-BOOK OF LAND AND MARINE ENGINES. 

carries with it a portion of carbon, the gaseous compound 
being known as carburetted hydrogen. 

A ton of 2000 pounds of average bituminous coal con- 
tains, say 1600 pounds, or 80 per cent, of carbon, 100 
pounds, or 5 per cent, of hydrogen, and 300 pounds, or 15 
per. cent, of oxygen, nitrogen, sulphur, sand, and ashes. 

But if this coal be coked, the 100 pounds of hydrogen 
driven off by heat will carry about 300 pounds of carbon 
in combination with it, making 400 pounds, or nearly 1000 
cubic feet of carburetted hydrogen gas. 

But still 1300 pounds of carbon (65 per cent, of the 
original coal) will be left, and, with the earthy matter, 
ashes, sulphur, etc., retained with it, the coke will weigh 
but about 1350 or 1400 pounds,— 67J to 70 per cent, of 
the original coal. 

The only proportions in which carbon and hydrogen 
combine with air in combustion are these : 

For every pound of carbon (pure coke), 12 pounds 
(equal to 159 J cubic feet) of air are required to combine 
intimately with it. 

For every pound of hydrogen, 36 pounds (equal to 
478^ cubic feet) of air are required to be similarly com- 
bined. 

Thus for every pound of carburetted hydrogen gas, 
being one-fourth pound of hydrogen and three-fourths of 
a pound of carbon, 18 pounds (equal to 239i cubic feet) 
of air are required to be combined with it. 

These are the elements and their combining proportions 
that have to be dealt with in a locomotive furnace. For 
every 2000 pounds of coal burned, the 400 pounds of 
carburetted hydrogen — the "gas"^ — require 95,700 cubic 
feet of atmospheric air at ordinary temperature, and the 
1300 pounds of solid carbon require 207,350 cubic feet 
of air. Practically, the gas from a ton of ordinary bitu- 



HAND-BOOK OF LAND AND MARINE ENGINES. 341 

minous coal requires 100,000 cubic feet of air for its com- 
bustion, while the remaining coke requires 200,000 feet. 
Thus the gaseous matter of the coal requires one-half as 
much air as is taken up by the solid coke. 

The heating value of any combustibles is exactly propor- 
tional to the quantity of air with which it will combine in 
combustion. Hence hydrogen, which combines with three 
times the quantity of air (oxygen) which would be taken 
up by carbon, has, for equal weights, three times the heat- 
ing value. Thus, the 100 pounds of pure hydrogen in a 
ton of coal have the same heating efficiency as that due to 
300 pounds of the remaining carbon or pure coke. 

It will now be seen that complete combustion cannot 
produce smoke, since smoke contains a quantity of un- 
burnt matter, and is in itself a proof of incomplete com- 
bustion. The products of perfect combustion are invisi- 
ble -^ being for carbon and oxygen, carbonic acid ; and 
for hydrogen and oxygen, invisible steam, which con- 
denses into water. 

The admission of heated air to furnaces or fire-boxes of 
locomotives can be of no practical value, since for every 
493° Fah. of heat added, its original bulk or volume is 
doubled ; treble at 1010° Fah. ; so that at 3000° Fah. the 
heated air in the interior of the furnace has six times its 
original volume. This makes it more unmanageable, and 
as its contained oxygen remains the same in weight, its 
mixture with the gas becomes more difficult, while, when 
mixed, it can do only the same work as before. 

Waste of Unburnt Fuel. — This generally arises from 
the brittleness of the fuel, combined with want of care on 
the part of the fireman, by which cause the fuel is made 
to fall into small pieces, which escape between the grate- 
bars into the ash-pit, and are lost. 

It is almost impossible to estimate the loss of fuel occa- 
29* 



342 



HAND-BOOK OF LAND AND MARINE ENGINES. 



sioned by carelessness and bad firing, but the amount 
which is unavoidable, even with care and good firing, has 
been ascertained by experiment to range from 2J to 3 per 
cent, of the fuel consumed. 

TABLE 

SHOWING THE TOTAL HEAT OP COMBUSTION OP VARIOUS PUELS. 



SORT OF FUEL. 



Equivalent 
in pure 
Carbon. 



Evaporative 

power in lbs. 

water from 

212° Fah. 



Total heat of 

combustion 

in lbs. water 

heated 1^ Fah. 



Charcoal 

Charred Peat 

Coke — good 

** mean 

<* bad 

Coal. — Anthracite 

Hard Bituminous — hardest 

<* f* softest.. 

Cooking coal 

Canning coal 

Long flaming splint coal 

Lignite 

Peat. — Perfectly air-dry... 
Containing 25 per ct. water 
Wood. — Perfectly air-dry 
Containing 20 per ct. water 



0.93 
0.80 
0.94 
0.88 
082 
1.05 
1.06 
0.95 
1.07 
1.04 
0.91 
081 
0.66 



0.50 



14.00 
12.00 
14.00 
13.20 
12.30 
15.75 
15.90 
14.25 
16.00 
15.60 
13.65 
12.15 
10.00 
7.25 
7.50 
5.80 



13500 

11600 

13620 

12760 

11890 

15225 

15370 

13775 

15837 

15080 

13195 

11745 

9660 

7000 

7245 

5600 



Spontaneous Combustion.— A great deal has been 
said and written on the subject of spontaneous combustion, 
and the danger likely to result from allowing steam-pipes 
to come in contact with the wood-work in buildings ; but 
as the temperature of superheated steam ranges from 300^ 
to 500^ Fah., it is only able to set fire to such substances 
as sulphur, gun-cotton, and nitro-glycerine. It is, perhaps, 
able to fire gunpowder, but certainly cannot ignite wood. 

It is only when dried wood, sawdust, or rags have been 
saturated by drying oil or other equivalents, that the 
temperature may be indefinitely raised, and finally reach 
400° or 500° Fah., or until the point of inflammability is 
attained.. This is caused by the oxidation of the oil and 
the agency of the air. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



343 



TABLE 

SHOWING THE NATURE AND VALUE OF SEVER AL VARIETIES OF 
AMERICAN COAIi AND COKE, AS DEDUCED FROM EXPERIMENTS 
BY PROFESSOR JOHNSON, FOR THE UNITED STATES GOVERNMENT, 



Designation of Fuel. 



BITUMINOUS. 

Cumberland, maximum 
* * minimum 

Blossburgh 

Midlothian, screened. 
" average . 

Newcastle 

Pictou 

Pittsburgh 

Sydney 

Liverpool 

Clover Hill 

Cannelton, la 

Scotch 



ANTHRACITE. 

Peach Mountain 

Forest Improvement.. 
Beaver Meadow No. 5. 

Lackawanna 

Beaver Meadow No. 3. 
Lehigh 

COKE.* 

Natural Virginia 

Midlothian 

Cumberland 



L313 
1.337 
1.324 
1.283 
1.294 
1.257 
1.318 
1.252 
1.338 
1.262 
1.285 
1.273 
1.519 

1.464 
1.477 
1.554 
1.421 
1.610 
1.590 

1.323 









52.92 
54.29 
53.05 
45.72 
54.04 
50.82 
49.25 
46.81 
47.44 
47.88 
45.49 
47.65 
51.09 

53.79 
53.66 
56.19 
48.89 
54.93 
55.32 

46.64 
32.70 
31.57 



10.7 

.9.44 

9.72 

8.94 

8.29 

8.66 

8.41 

8.20 

7.99 

7.84 

7.67 

7.34 

6.95 

10.11 
10.06 
9.88 
9.79 
9.21 
8.93 

8.47 
8.63 
8.99 






^-2 

31 






573.3 
532.3 
522.6 

438.4 
461.6 
453.9 
478.7 
384.1 
386.1 
411.2 
359.3 
360.0 
369.1 

581.3 
577.3 
572.9 
493.0 
526.5 
515.4 

407.9 
282.5 
284.0 






2.13 
4.53 
3.40 
3.33 
8.82 
3.14 
6.13 
.94 
2.25 
1.86 
3.86 
1.64 
5.63 

3.03 
.81 
.60 
1.24 
1.01 
1.08 

5.31 

10.51 

3.55 



<4 M «5 



42.3 
41.2 
42.2 
49.0 
41.4 
44.0 
45.0 
47.8 
47.2 
46.7 
49.2 
47.0 
43.8 

41.6 
41.7 
39.8 
45.8 
40.7 
40.5 

48-3 
68.5 
70.9 



* See page 338. 



344 



HAND-BOOK OF LAND AND MARINE ENGINES. 



TABLE 

SHOWING SOME OF THE PROMINENT QUALITIES IN THE PRINCI- 
PAL AMERICAN WOODS. 



Species. 



Hickory 

White Oak.. 
Black Oak... 

Red Oak 

Beech 

Birch 

Maple ..^ 

Yellow Pine 
Chestnut... 
Pitch Pine. 
White Pine.. 



1.07 



1.05 
0.98 
0.90 
0.90 



0.87 0,47 



goo 



0.71 



0.68 
0.59 
0.63 
0.64 






0.66 



0.66 
0.58 
0.57 
0.61 



0.38 



sis 



3000 
3000 
3000 
3000 
3000 
3000 
3000 
2800 
3000 
2800 
2800 



o 


^ <i> 




^ 3 




's ^ 


S'^ 


P> 


Si^ 


td o 


^s 


03 2 


S u 


rj CS 


fin 


a 


44.69 


25 


21.62 


25 


23.80 


25 


22.43 


25 


32.36 


25 




25 


27.00 


25 


24.63 


23 


25.25 


25 


19.04 


23 


18.68 


23 



§1 



S'2 

<^ o 



4496 
3821 
3254 
3254 
3236 



2700 
2463 
2333 
1904 

1868 



1.00 
0.81 
0.71 
0.69 
0.65 



0.57 
0.54 
0.52 
0.43 
0.42 



TABLE 

SHOWING THE RELATIVE PROPERTIES OF GOOD COKE, COAL, 
AND WOOD. 



Name of Fuel. 


"o 

a 

u 

3 
o 

SI 


1 

1 

xi 
o 

u 
bo 


.2 
d 

1 

« 

O 

ft 


O CD 

Si 


o « 

r 


O A 

11 
li 


a a 
IP 


Is 

o fi 2 

ill 

|g.S 


'3 o 

§1 


Coke 


63 

80 
30 


4300 
4000 

2800 


95 
88 
20 


80 

44 

107 


28 
51 
21 


22.4 
32.0 
16 


13 
10 

60 


8i 
6 

^ 


100 
71 
29 


Coal 


Wood 









HAND-BOOK OF LAISTD AND MARINE ENGINES. 



345 



TABLE 

OF TEMPERATURES REQUIRED FOR THE IGNITION OF DIFFERENT 
COMBUSTIBLE SUBSTANCES. 



Substances. 


Temperature 
of Ignition. 


Remarks. 


Phosphorus 


140° 


Melts at 110^. 


Bisulphide of carbon 






vapor 


300° 
374° 


Melts at 130°. 

Used in percussion caps. 


Fulminating Powder 


Fulminate of Mercury ... 


392° 


According to Legue and 
Champion. 


Equal parts of chlorate 






of potash and sulphur. 


395° 




Sulphur 


400° 


Melts, 280^; boils, 850°. 


Gun-cotton 


428° 


According to Legue and 
Champion. 






Nitro-glycerine 


494° 


a a a 


Rifl,e-powder 


550° 
563° 


(( (( (< 
a (t ti 


Gunpowder, coarse 


Picrate of mercury, lead 






or iron 


565° 


H (( kl 


Picrate powder for tor- 


pedoes 


570° 


a a a 


Picrate powder for mus- 






kets 


576° 


(( It n 


Charcoal, the most in- 






flammable willow used 






for gunpowder 


580° 


According to Pelouse and 
Fremy. 






Charcoal made by distill- 






ing wood at 500° 


660° 


(( (( (( 


Charcoal made at 600°.... 


700° 


i( (( n 


iPicrate powder for can- 






non 


716° 
800° 




Very dry wood, pine 


** *' *' oak 


900° 




Charcoal made at 800°.... 


900° 





It will be seen by the above table that the most com- 
bustible substances generally considered very dangerous, 
will only ignite by heat alone at a high temperature, so 
that for their prompt ignition it requires the actual contact 
of a spark. 



346 HAND-BOOK OF LAND AND MARINE ENGINES. 

GASES. 

All substances, whether animal, vegetable, or mineral, 
consisting of carbon, hydrogen, and oxygen, when exposed 
to a red heat, produce various inflammable elastic fluids, 
capable of furnishing artificial light. We perceive the 
evolution of this elastic fluid during the combustion of 
coal in a common fire. 

Bituminous coal, when heated to a certain degree, swells 
and kindles, and frequently emits remarkably bright 
streams of flame, and after a certain period these appear- 
ances cease, and the coal glows with a red light. 

The flame produced from coal, oil, wax, tallow, or other 
bodies which are composed of carbon and hydrogen, pro- 
ceeds from the production of carburetted hydrogen gas, 
evolved froM the combustible body when in an ignited 
state. 

If coal, instead of being burnt in the way now stated, 
is submitted to a temperature of ignition in close vessels, 
all its immediate constituent parts may be collected. The 
bituminous part is distilled over in the form of coal-tar, 
etc., and a large quantity of an aqueous fluid is disengaged 
at the same time, mixed with a portion of essential oil and 
various ammoniacal salts. 

A large quantity of carburetted hydrogen, carbonic 
oxide, carbonic acid, and sulphuretted hydrogen also make 
their appearance, together with small quantities of cyan- 
ogen, nitrogen, and free hydrogen ; and the fixed base of 
the coal alone remains behind in the distillatory apparatus 
in the form of a carbonaceous substance called coke. An 
analysis of coal is thus ,efiected by the process of destructive 
distillation. 

Hydrogen. — Hydrogen is the lightest of all known 
gases, its specific gravity being only 0*06896. This gas is 
colorless, and, when perfectly pure, inodorous. It has a 



HAND-BOOK OF LAND AND MARINE ENGINES. 347 

powerful affinity for oxygen, and is therefore eminently 
combustible. Intense heat is developed by the combus- 
tion of hydrogen in oxygen gas, and but little light. 

Carbon. — Carbon is well known under the form of 
coke, charcoal, lamp-black, etc. It is one of the principal 
constituents of all varieties of coal, and is the basis of the 
illuminating gases. It is a colorless and inodorous gas, 
rather lighter than common air, having a specific gravity 
of 0*9727, is sparingly absorbed by water, and does not 
precipitate lime-water. It is inflammable, burning with a 
beautiful blue flame ; the product of its combustion is car- 
bonic acid. 

Carbon unites with hydrogen in many proportions, and 
many of these compounds are produced during the dis- 
tillation of coal ; but the only two of importance are car- 
buretted hydrogen and defiant gas. 

Carburetted Hydrogen. — Carburetted hydrogen is 
abundantly formed in nature, in stagnant pools, ditches, 
etc., wherever vegetables are undergoing the process of 
putrefaction ; it also forms the greater part of the gas ob- 
tained from coal. Carburetted hydrogen consists of 100 
volumes of vapor of carbon, and 200 of hydrogen. It is 
colorless and almost inodorous ; it is not dissolved to any 
extent by water, and is much lighter than atmospheric 
air, its density being 0*5594. It is very inflammable, 
burning with a strong yellow flame. The products of its 
combustion are carbonic acid and water. 

Carburetted hydrogen, or coal-gas, when freed from the 
obnoxious foreign gases, may be propelled in streams out 
of smair apertures, which, when lighted, form jets of flame, 
which are called gas-lights. 

defiant Gas. — defiant gas is a product of the distilla- 
tion of oil, resin, and also of coal, when the process is well 
conducted. It is colorless, tasteless, and without smell 



348 HAND-BOOK OF LAND AND MARINE ENGINES. 

when pure. Water dissolves about one-eighth of its ^ulk 
of this gas. It is formed of two volumes of hydrogen, and 
two of the vapor of carbon condensed into one volume. 

Olefiant gas burns with an intense white light, and 
requires a larger portion of oxygen for its combustion, one 
volume of the gas requiring not less than three volumes 
of pure oxygen, or fifteen volumes of atmospheric air for 
decomposition. The products of the combustion are water 
and carbonic acid. 

Nitrogen. — Nitrogen is one of the constituents of coal. 
It has the properties of extinguishing burning bodies, and 
is not absorbed by water ; its specific gravity is 0.9760, 
being lighter than common air, in which it forms a con- 
stituent part. 

Liquefaction of Gases. — Many of the gases have already 
been brought into the liquid state by the conjoint agency 
of cold and compression, and all of them are probably sus- 
ceptible of a similar reduction by the use of means suffi- 
ciently powerful for the required end. 

They must consequently be regarded as the superheated 
steams or vapors of the liquids into which they are com- 
pressed. 

Comppession and Dilatation of Gases. — When a gas 
or vapor is compressed into half its original bulk, its press- 
ure is double ; when compressed into a third of its original 
bulk, its pressure is treble ; when compressed into a fourth 
of its original bulk, its pressure is quadrupled ; and gen- 
erally the pressure varies inversely as the bulk into which 
the gas is compressed. 

So in like manner if the volume be doubled, the press- 
ure is made one-half of what it was before — the pressure 
being in every case reckoned from 0, or from a perfect 
vacuum. 

Thus, if we take the average pressure of the atmosphere 



HAND-BOOK OF LAND AND MARINE ENGINES. 



349 



at 14*7 pounds on the square inch, a cubic foot of air, if 
suffered to expand into twice its bulk by being placed in 
a vacuum measuring two cubic feet, will have a pressure 
of 7 '35 pounds above a perfect vacuum, and also of 7*35 
pounds below the atmospheric pressure ; whereas, if the 
cubic foot be compressed into a space of half a cubic foot, 
the pressure will become 29*4 pounds above a perfect vac- 
uum, and 14*7 pounds above the atmospheric pressure. 

The specific gravity of any one gas to that of another 
will not exactly conform to the same ratio under different 
degrees of heat, and other pressures of the atmosphere. 

Water, as before stated, is composed of two gases, oxy- 
gen and hydrogen — the weight of a cubic foot of hydrogen 
being '005592 pounds, and of half a cubic foot of oxygen 
'0044628 pounds avoirdupois. One cubic foot of hydro- 
gen and half a cubic foot of oxygen combined form one 
cubic foot of steam. One cubic foot of steam, therefore, 
which results from the union of these gases, must weigh 
•05022 pounds. 




A Gang of Steam-Boilers. 



30 



850 HAND-BOOK OF LAND AND MARINE ENGINES. 

STEAM-BOILERS. 

Since the introduction of steam as a motive power, a 
great variety of boilers have been designed, tried, and 
abandoned ; while many others, having little or no merit 
as steam generators, have their advocates, and are still con- 
tinued in use. Under such circumstances, it is not sur- 
prising that quite a variety of opinions are held on the 
subject. This difference of opinion relates not only to the 
form of boilers best adapted to supply the greatest quan- 
tity of steam with the least expenditure of fuel, but also 
to the dimensions or capacity suitable for an engine of a 
given number of horse-power ; the mere arithmetic of the 
question remaining up to this day unsettled. 

In designing a steam-boiler, there are many important 
points to be considered, such as cost, proper materials, 
strength to bear the intended pressure, quantity of steam 
to be furnished in a given time, space occupied, weight, 
circulation of water, water room, facilities for cleaning and 
repairing, steam room, heating and grate surface, area 
through flues, etc. 

The three most important objects to be attained in the 
design, construction, and use of steam-boilers are, "safety," 
" durability," and " economy." To insure " safety," it is 
necessary that the boiler should be designed in accordance 
with true mechanical principles, avoiding as much as pos- 
sible ther evils of unnatural strains and unequal expansion 
and contraction ; due regard must also be paid to the 
quality of the material and character of the workmanship 
employed in its construction. 

We have no data by which to establish the general " du- 
rability " of any class of steam-boilers, but experience has 
shown, in all individual cases, that the durability of a steam- 
boiler depends on the quality of the material and the 
character of the workmanship used in its construction, the 
facilities afforded for cleaning, repairing, and renewal of 



HAND-BOOK OF LAKD AND MARINE ENGINES. 351 

any of its parts, and also the care and management after 
being put in use. 

"Economy" in the generation of steam depends to a 
certain extent on the character or quality of the metal 
of which the boiler is made ; as it is a well known fact, 
that the thicker the iron, and the poorer its conducting 
qualities, the greater will be the loss of heat ; when by 
using a superior quality of iron, one whose tensile strength 
and conducting powers are both very great, we lessen the 
resistance to the passage of the heat from the furnace to 
the water and greatly increase the economy of the boiler. 




Cylinder Boiler. 

It is also well known to engineers that some qualities 
of iron are two and a half times stronger than others ; con- 
sequently, if a boiler be made of the poorer iron, that 
would be as strong as J inch of the best iron, it would be 
necessary to use plates I of an inch thick. Even then 
the heavy boiler would be weaker than the light one, from 
the fact that the heavy plates would sustain greater injury 
in the making. In point of economy and durability, the 
light boiler would be far superior to the heavy one. 

Cylinder Boilers. — The plain cylinder boiler, one of the 
earliest forms of steam-generators, and, until quite recently, 
the one most extensively used, is fast passing out of use, 
particularly in localities where space is limited and fuel 
expensive. Its advantages were its lightness and moder- 



352 



HAND-BOOK OF LAND AND MARINE ENGINES. 



ate first cost, and that it afforded better facilities for clean- 
ing, repairing, or the renewal of any of its parts than any 
Other type of boiler. It also possessed peculiar advan- 
tages for rolling-mill and blast-furnace purposes, as it re- 
quired less care, and was least dangerous on account of 
the great body of water it contained. Its disadvantages 
were its extreme length and wastefulness of fuel. 




Flue Boiler, 



Flue Boilers. — The advantages of this type of boilers 
over the former are, that it occupies less space, requires 
less fuel, and steams better in consequence of its extra 
heating surface. Like the cylinder, it is a favorite for roll- 
ing-mill and blast-furnace purposes, as it affords facilities 
for return draught ; but it has the disadvantages of extra 
weight, consequently, increased first cost, and that it is 
more difBcult to clean or repair. It also requires more 
care on account of the liability of the fliues to become 
overheated and collapse in case the regular supply of 
water should be neglected. 

Tubular Boiler. — This type of boiler possesses many 
advantages, in an economical point of view, over either the 
cylinder or flue, as it occupies less space, requires less fuel to 
evaporate a certain quantity of water in a given time, and, 
in consequence of the small diameter of the tubes, its lia- 
bility to collapse is entirely obviated. But it has the dis- 
advantage of requiring more care than either of the former, 



HAND-BOOK OF LAND AND MARINE ENGINES. 



353 



and is almost impossible to clean or repair. The double- 
deck boiler, a combination of the cylinder and tubular, is 
a very safe and economical type of boiler, as it occupies 
less floor space than either the cylinder, flue, or single 
tubular. It also presents an immense amount of heating 
surface, and, in consequence of the great body of water it 
^contains, obviates the danger of the water becoming low, 
excepting in cases of extreme neglect. 




Tubular Boiler. 



Locomotive Boilers. — This kind of boiler, though not 
in very general use for stationary purposes, when well pro- 
portioned for its work, is very economical, as it occupies 
but little space, presents an immense amount of heating 
surface, steams very rapidly, and, when well constructed, 
is compact and powerful. Its great disadvantages arise 
from the complication of its parts, which makes it ex- 
tremely difiicult to clean or repair, consequently, it is 
liable to burn out; besides, as the water space is limited, it 
requires special care and attention. 



STEAM-DOMES. 

The advantages claimed to be derived from the steam- 
dome are, that it acts as a steam reservoir, and also an 
anti-primer, in consequence of being further removed from 
the water than any other part of the boiler, ♦hich is true 
30^ X 



354 HAND-BOOK OF LAND AND MARINE ENGINES. 

to a certain extent ; but as regards its advantages as a 
steam reservoir, it can easily be shown that an ordinary sized 
steam-dome adds very little to the steam room of a boiler. 

Fop instance, a boiler 48 inches in diameter and 20 feet 
long would contain 251 cubic feet of space ; if we take | 
of that as water space, we will have left about 63 cubic 
feet for steam room. Now suppose we take a steam-dome 
24 inches in diameter and 2 feet high, we gain only 6 
cubic feet of steam room, or about enough of steam to fill 
the cylinder of an engine 12 inches in diameter and 24 
inch stroke, and about 5 times, even if worked expan- 
sively. 

Now, with respect to its advantages as an anti-primer, 
it appears to be taken for granted that the higher the 
point at which the steam is taken from the boiler, the 
drier it is likely to be ; but the cooling effect on the steam, 
by domes of large diameter exposed to the atmosphere, 
seems to be entirely lost sight of, as it is a well-known 
fact that, when an engine is at work, the steam rushes into 
and through the dome with great velocity, and in its pass- 
age is liable not only to take with it a great quantity of 
water, but have its temperature lowered by coming in 
contact with so much surface exposed to the action of 
the atmosphere. It frequently happens that the steam 
taken from a dome is more wet than that in any other part 
of the boiler. 

The pesepvoir of powep in a boilep is not so much in 
the steam as in the heated water. With a working press- 
ure of 60 pounds, each cubic foot of steam in the boiler 
will produce only 4*65 cubic feet of steam at atmospheric 
pressure ; but 1 cubic foot of water in the boiler will pro- 
duce nearly 35 times that amount, for at 60 pounds press- 
ure the temperature of the water is 307*5°, or 95*5° above 
the boiling-point at atmospheric pressure ; and, as every 



HAND-BOOK OF LAND AND MAKINE ENGINES. oOO 

degree of heat added to water already at 212° may be 
taken as competent to generate 1*7 cubic feet of steam, 
95*5° will produce 162*35° cubic feet, or nearly 36 times 
as much as 1 cubic foot of steam at 60 pounds pressure. 

It will be seen from the above, that, notwithstanding 
the general opinion that the presence of a steam-dome is 
essential for obtaining dry steam and as a remedy for 
priming, it should be regarded as not only a useless and 
expensive appendage to a boiler, but a source of real 
weakness and danger ; the practice of cutting a dome-hole 
in the shell of a boiler, without providing for the weaken- 
ing of the plate by some other means, should be looked 
upon as a very mischievous and dangerous practice. 

When it becomes necessary to have a dome, as in case 
of limited steam room, or where the arrangement of the 
tubes or flues is such as to make it necessary to carry the ' 
water high in the boiler, the hole in the plate under the 
dome should not be cut larger than sufficient to allow a 
free escape of the steam from the boiler to the dome, or 
to admit of a convenient adjustment of the dome-braces. 

MUD-DRUMS. 

When we consider the short life of the mud-drum, 
which rarely exceeds six or seven years, and also the ex- 
pense of removing it and replacing it with a new one, its 
use in any case becomes a question of doubtful economy. 
Steam users and engineers for a long time entertained the 
belief that mud-drums were beneficial, inasmuch as they 
imparted extra heat to the feed-water, and retained the 
mud that would otherwise have been carried iuto the 
boiler. Experience, however, has shown this to be a grave 
error, as mud^drums impart very little heat to the feed- 
water, and retain nothing but the earthy matter which is 
held in suspension in the water, while all the destructive 



356 HAND-BOOK OF LAND AND MARINE ENGINES. 

carbonates that are held in solution are carried into the 
boiler. 

A good deal has been said and written, and many 
theories advanced, to account for the pitting, or honey- 
combing, of mud-drums, but the mysterious manner in 




Mud-DrumSi 

which it occurs, and its peculiar character, have not as 
yet been fully explained, as scientific men are still unable 
to assign even a plausible cause. But the most probable 
cause for this singular pitting or rotting away might be 
assigned to the location of the drum, as it receives nearly 
all the heat imparted to it on the upper side, with not 
enough on the lower side to keep the iron perfectly dry 
and prevent the rusting away of the plates and rivet- 
heads. 

SETTING BOILERS. 

In " setting " or *' putting in " boilers, as it is sometimes 
called, all the surface possible should be exposed to the ac- 
tion of the heat of the fire,-^not only that the heat may be 
thus more completely absorbed, but that a more equal ex- 
pansion and contraction of the structure may be obtained. 
And in cases where convenience serves, it will be found ad- 
vantageous to return the draught through a brick flue over 
the top of the boiler, in order to equalize the heat and, 
consequently, the expansion ; and although this arrange- 



HAND-BOOK OF LAi^TD AND MARINE ENGINES. 357 

ment does not facilitate the generation of steam, yet fuel 
will be saved by a more complete application of the heat, 
and the prevention of radiation from the upper part of the 
boiler. 

Convenient openings should be arranged in the brick- 
work to facilitate the cleaning of the boiler on the outside, 
as that part of the shell exposed to the action of the draught 
is liable to become permanently coated with soot and ashes, 
rendering a great portion of the heating surface nearly 
worthless ; the dijflaculty experienced in removing these 
non-conductors from the under side of the boiler generally 
arises from an improper arrangement at the time of set- 
ting, and a want of space. 

Boilers should be set with as little brickwork in con- 
tact with the shell as practicable. No mortar should be 
used where it can come in contact with the plates, but 
fire-clay should be used instead for the whole setting of 
the boiler. 

Long Boilers are often hung by means of loops riveted 
to the top of the boiler, and connected to cross-beams and. 
arches, resting on masonry above the boiler, by means of 
hangers. This is a very mischievous arrangement, unless 
turn-buckles, or some other contrivance, are used to main- 
tain a regular strain on all the hangers, as long boilers ex- 
posed to an excessive heat are apt to lengthen on the 
lower side and relieve the end hangers of any weight ; con- 
sequently, the whole strain is transmitted to the central 
hanger, which has a tendency to draw the boiler out of 
shape, which, in many instances, induces excessive leak- 
age, rupture, and eventually explosion. 

The most permanent practical method of setting boilers 
is to rivet cast-iron brackets or knees to their ends and 
centre, about 12 feet apart, resting on brick piers, as by 
that arrangement one end can settle without injuriously 



853 HAND-BOOK OF LAND AND MABINE ENGINES. 

affecting the other. These brackets, in some instances, 
rest on small rolls arranged in a flanged seat, in order to 
prevent the piers from being forced out when the boiler 
expands. 

All boilers should be set with an incline of not less than 
1 inch in 20 feet to the end in which the blow-off is situ- 
ated, in order that the water may run out by its own 
gravity. The blow-off should be located in the back or 
coldest end, as the mud and deposits always seek that part 
where the boiling currents are least violent. 

EXPANSION AND CONTRACTION OP BOILERS. 

A great difficulty to be contended with in the manage- 
ment and working of steam-boilers arises from the un- 
equal expansion and contraction of parts of the structure. 
In some instances these are so great as to be the cause of 
more " wear and tear " than any other condition to which 
the boiler is subjected ; consequently, in raising steam on 
new boilers, or those that have been blown out and allowed 
to cool down, great care should be taken in allowing the 
fire to burn moderately, as otherwise the boiler may be 
seriously weakened, if not permanently injured; more par- 
ticularly so in the case of flue and tubular boilers, as the 
flues or tubes, being exposed to the direct action of the 
fire, and generally of a thinner material than the shell, 
expand much quicker, and, as a result, the ends of the 
boiler are forced outward, and the whole structure ex- 
posed to an enormous strain. 

When the flues of boilers are placed nearer to the 
bottom than to the top, the strain, from unequal expansion 
and contraction, is often such that the plates of the under 
part of the outer shell are torn or broken ; and, in other 
cases, leakages take place in positions where they are most 
difficult to discover. 



HAND-BOOK OF LAND AND MARINE ENGINES. 359 

When a boiler is set with only a small portion of its 
bottom exposed to the heat, and a great portion of the 
structure exposed to the atmosphere, as is the common 
practice, a powerful action is left at full liberty to work 
out most injurious results. The heat will expand that 
portion of the boiler to which it is applied ; while the 
other portion exposed to the cold atmosphere will con- 
tract. Thus the two forces are left to exert their respect- 
ive powers against each other, tending to tear the boiler 
asunder by means almost imperceptible. 

A boiler under steam is often strained, especially in a 
longitudinal direction, more by the greater dilation of the 
tubes compared with the shell, or by the unequal expan- 
sion of the top and bottom of the shell, than by the actual 
steam pressure. The persistent leakage often experienced 
at the seams, along the bottom of horizontal internally 
fired boilers, might in most cases be ascribed to the dif- 
ference in temperature of the water and steam at the bot- 
tom and top of the boiler ; but in some cases the leakage 
is principally caused by the longitudinal straining of the 
bottom of the shell, due to the greater expansion of the 
tubes, especially when the firing is forced in getting up 
steam after the boiler has been at rest. 

As this straining would not take place in testing the 
boiler by hydraulic pressure in the usual manner, this 
leakage would not be produced. It follows, from the 
above considerations, that a hydraulic test might fail to 
indicate weakness which would be produced and made ap- 
parent by steam pressure. 

TESTING BOILERS. 

Experience has shown that, let a boiler be ever so care- 
fully designed and constructed, there will still remain an 
element of doubt as to its actual strength, since the 



360 HAND-BOOK OF LAND AND MARINE ENGINES. 

material may have sustained injuries in the process of 
construction which may have escaped detection. 

In the case of a new boiler, even by a first-rate manu- 
facturer, to say nothing of original and hidden flaws in 
the plates and castings, there is always a possibility of 
defects, such as bad welding, careless riveting, plates burnt 
in flanging or cracked in bending, and many other defects 
that may be traced to reckless negligence or want of skill ; 
consequently, the only means we have of ascertaining, with 
any degree of certainty, the safety of a boiler is by the 
application of cold water pressure, as many cases of 
dangerous defects, which the strictest scrutiny of the 
practical boiler-maker failed to detect, have been brought 
to light by means of the hydraulic test. 

There are many forms of boilers which do not admit 
of anything like a proper examination, as, for instance, 
tubular boilers, in which the shell of the boiler is filled 
with tubes nearly to the water line ; also many forms of 
marine boilers, whose construction is so irregular and 
complicated as to defy even an approximate calculation of 
their strength or condition. 

With regard to the various modes of testing by hy- 
draulic pressure, that commonly adopted is to pump water 
in until the desired pressure be reached. The condition 
of the joints and rivets is then looked to, and any very 
conspicuous distortion, leak, or defect marked ; and in cases 
of permanent distortion or flattening of tubes or flues, the 
injured parts should be immediately removed and repaired 
or renewed, as the injury to the tube or flue is liable to be 
aggravated by subsequent tests, and eventually result in 
rupture or collapse. 

Some advocate the method of marking the leaky 
joints while the pressure is on, and then lowering the 
pressure for the purpose of calking ; this is decidedly 
wrong. Boilers should never be calked while under steam 



HAND-BOOK OF LAND AND MARINE ENGINES. 361 

or water pressure, however light, as the jarring induced by 
the calking is liable to spring the seams, and cause fresh 
leakage in different parts of the boiler. 

Some recommend the employment of hot water for test- 
ing boilers, as it assimilates, more than cold water, the 
conditions under which the boiler is placed when at work. 
But the \yater for test should never be more than moder- 
ately warm, as the hydraulic test is comparatively worth- 
less without a thorough examination of the boiler at the 
same time ; and it is impossible to do so in cases where hot 
water is used, in consequence of the presence of so much 
heat under and around the boiler. 

In some cases, the plan has been adopted of filling the 
boiler with water, closing every outlet, and putting fire to 
it. As water expands about -^-^ in volume in rising from 
60° to 212°, the rise of temperature as the water becomes 
heated will cause a corresponding increase of pressure, 
and, from the regularity with which the pressure rises, any 
leak that may occur in the boiler will be easily noticed by 
the jerks or starts of the steam-gauge hand. But the 
wisdom of this method is extremely doubtful, as it involves 
a certain amount of danger, and prevents the possibility of 
examining the boiler in the parts most likely to be affected 
during the test. 

In whatever manner a boilep is tested, great care should 
be taken to obtain the exact amount of pressure employed, 
for the reason that safety-valves are very often unreliable, 
particularly so when water pressure is used, and spring- 
gauges are not always to be trusted under such circum- 
stances ; in all cases, when the cold water test is applied, 
two gauges should be used ; for, although a boiler cannot 
explode under the hydr&ulic test, yet many serious accidents 
have occurred by boilers giving way under such circum- 
stances. 
31 



362 HAND-BOOK OF LAND AND MARINE ENGINES. 

The hydraulic test meets with opposition from some 
engineers on the ground that it does not tell the actual 
strength of the boiler; but the same objection might be 
urged against the steam and expansion tests, as there is no 
accurate method of ascertaining the. strength of a boiler 
but to burst it. The hydraulic test is not meant for per- 
fectly sound boilers, but for the detection of weaknesses in 
certain parts, and is generally successful for that purpose, 
if well conducted. 

The injuries arising from an excessive application of the 
hydraulic test are most likely to occur to flue boilers, as, 
whenever flues subjected to external pressure depart from 
the true cylindrical form, or form of greatest resistance, 
they are liable to collapse, even under very low pressure. 

Sound Test. — The sound test is generally applied to 
all accessible parts of the boiler, such as the upper part 
of the shell, crown-sheet, crown-bars, angle iron, and braces, 
which is done by tapping the parts to be tested lightly 
with a small steel hammer. The experienced boiler-maker 
or inspector can easily tell, by the eff*ect of the sound on 
the ear, whether the part subjected to the blow is sound or 
not. But whether by sound, expansion, or hydraulic press- 
ure, the testing of boilers requires the utmost care and ex- 
perience, and should never be applied to any boiler unless 
all the conditions are fully understood, such as the di- 
ameter, age and condition, character of seams, etc.; nor even 
then, except by persons who fully comprehend the object 
and efiect of the test. 

NEGLECT OP STEAM-BOILERS. 

Perhaps no appliances connected with factories, and 

other places where power is used, ate more sadly neglected 
than steam-boilers, and nothing can be more surprising 
than this fact, when we consider the important part they 



HAND-BOOK OF LAND AND MARINE ENGINES. 363 

occupy in the manufacturing arts. It would be difficult 
to assign any reasonable cause for this neglect, except that 
it may arise from the fact that nearly the whole attention 
of builders and leading engineers has been concentrated 
on the improvement and perfection of the steam-engine ; 
and the practical engineer, following the example set by 
the leaders, generally devotes all his attention to the engine. 

In the majority of cases boilers are not cleaned half as 
often as they should be. When the water is hard, and 
scale accumulates on the sides or flues of the boiler, solvents 
are very often resorted to to remove the scale. After the 
scale has been thrown down, it accumulates on the bottom 
of the boiler, and, if not removed at once, it becomes con- 
glomerated; forms a heavy coating ; and if the boiler is ex- 
ternally fired, the bottom is liable to be burned through. 

The yearly report of the Hartford Steam-Boiler Inspec- 
tion and Insurance Company shows that nearly half of the 
whole number of defective boilers became so on account 
of incrustation and deposit of sediment ; and, strange as 
it may seem, there were 40 per cent, more dangerous cases 
from the deposit of sediment than from incrustation and 
scale. The same report further shows that more than one- 
half the defective boilers from other causes are due to care- 
less and incompetent management, proving clearly that a 
large number of cases from which explosions might be 
expected may be traced to a direct cause. 

CARE AND MANAGEMENT OF STEAM-BOILERS. 

Familiarity with steam machinery, more especially with 
boilers, is apt to beget a confidence in the ignorant which is 
not founded on a knowledge of the dangers by which they 
are continually surrounded, but is the offspring of conceit 
and folly; while contact with steam, and a thorough ele- 
mentary knowledge of its constituents, theory, and action, 



364 HAND-BOOK OF LAND AND MARINE ENGINES. 

only incline the intelligent engineer and fireman to be 
more cautious and energetic in the discharge of their duty. 

As the boiler is the source of power, and the place 
where the power to be applied is first generated, and also 
the source from which the most dangerous consequences 
may arise from neglect or ignorance, it should attract 
the special attention of the engineer, as, from the hour it 
is set to work, it is acted upon by destroying forces, more 
or less uncontrollable in their work of destruction. 

These forces may be distinguished as chemical and me- 
chanical. In most cases they operate independently, yet 
they are frequently found acting conjointly in bringing 
about the destruction of the boiler, which will be more or 
less rapid according to circumstances, care, management, etc. 

One of the most common causes of deterioration in 
steam-boilers, and also leakage of the seams and under 
side and at the junctions of the tube* and tube-sheets, is 
the reckless practice of blowing out the boiler while still 
hot, and filling it again with cold water. Under such cir- 
cumstances, the contraction of the crown-sheet, tube-sheets, 
and tubes is so rapid and unequal, that, if persisted in, 
it eventually results in the ruin of the boiler. 

Boilers should never be filled with cold water while they 
are hot, as it has a very injurious effect, causing severe con- 
traction of the seams and stays, which very often induces 
fracture of stays or leakage in the seams and tubes. 

Many boilers, well constructed and of good material, 
have been ruined by being blown out under a high press- 
ure of steam, and then suddenly filled with cold water. 

The tubes of boilers being generally of thinner material 
than the shell, consequently cool and contract sooner ; for 
this reason, the boiler should never be filled with cold 
water while the tubes are hot. 

The boiler should always be allowed to stand for several 



HAND-BOOK OP LAND AND MARINE ENGINES. 365 

hours, or until it is cold, before the water is run out ; the de- 
posit of mud and scale will then be found to be quite soft, 
and can be easily washed out with a hose from all acces- 
sible parts. 

There seems to be an impression on the minds of some 
engineers that blowing out a boiler under pressure has a 
tendency to remove the deposits of mud from the boiler » 
but experience has shown this to be a very grave mistake. 

Tubes and flues should be frequently swept out, at 
least once a week. This can be done, in either land or 
marine boilers, while the engine is in motion, by covering 
the fire in the furnace, either in front of or under the 
tubes to be cleaned, with a thick layer of fresh coal, and 
cleaning one set of tubes at a time. Accumulations of 
salt frequently occur in the tubes of marine boilers, which 
are induced by leakage of the tubes or tube-sheet ; such 
accumulations should be removed as soon as discovered, 
and the tube thoroughly swept, or, if need be, bored out 
with a steel scraper, in order to prevent the part from 
becoming burnt through. It frequently becomes necessary 
to direct a steam-jet on the deposit before it can be effectu- 
ally removed. 

Tubes frequently become leaky in consequence of 
becoming split, or their ends at the tube-sheet being 
burned off. In the former case they have, of necessity, 
to be plugged, which can be done effectually by driving 
pine plugs solid into their ends ; although, in some cases, 
it becomes necessary to run a long bolt through the inside 
of the tube, with a flange and packing at each end ; in 
the latter case, they can be made tight by means of 
wrought-iron ferrules. 

When two op more boilers are connected by feed- 
pipes, the stop-valves on each should be shut off every 
night, or whenever they are not working, as the water is 
31^ 



366 HAND-BOOK OF LAND AND MARINE ENGINES. 

liable to escape from one to the other, on account of 
variation in the pressures; and, as a consequence, when 
the water in one is up to, or even above, the proper level, 
the tubes or flues in the other are very often bare of 
water. 

It is no uncommon thing in factories to have two boilers 
for the same engine, in order that one may be out of use 
while the other is working ; but, while this is an accommo- 
dation, it is not always economy, as boilers wear out faster 
when not in use, by oxidizing and corroding, than if 
moderately worked. It will be found more economical 
to work with extra boiler room than to have one or more 
standing. It will also tend to prevent priming. The 
furnaces will be more economically worked with a thick 
fire than with a thin one, by allowing the heat to accumu- 
late, thereby maintaining a high temperature in the 
furnace with slow combustion. 

The furnace door should never be allowed to remain 
open longer than a sufficient time to clean and replenish 
the fire, as the contraction of the tubes and flues, induced 
by the cooling down of the furnace, has a very mischiev- 
ous eflTect on all parts of the boiler exposed to the cold 
draught, more particularly so when the fire is thin, and 
the temperature in the furnace is of a high degree. 

The feed -water should be sent into the boiler as hot as 
possible, as, if it be forced in at a low temperature, it will 
impinge on that portion of the boiler with which it comes 
in contact, and, as a result of the continual expansion 
and contraction induced by the varying temperature of 
the water, the boiler is liable to crack and become leaky. 

Where economy of fuel is no object, as is often the 
case at coal-mines, saw-mills, and wood-working establish- 
ments, a very inexpensive way of averting the disastrous 
eflfects of pumping cold water into boilers is to introduce 




HAND-BOOK OF LAND AND MAKINE ENGINES. 867 

the feed-pipe into the back end of the boiler, cawying it 
forward about three-quarters the length of the boiler, and 
then returning it to the 
back end where the water 
is discharged into the 
boiler. By this arrange- 
ment the water will have 

. ^ 1 . Heater Pipe. 

a temperature nearly 

equal to that of the w^ater in the boiler when discharged 
from the pipe. 

If, from neglect op any other cause, the water in the 
boiler should become dangerously low, the fire-doors and 
damper should be immediately thrown open for the pur- 
pose of admitting the cold air to the heated plates, and the 
fire withdrawn as soon as possible. Under such circum- 
stances, no attempt should be made to introduce cold water 
into the boiler, as it might be attended with the most dis- 
astrous results. Nor should the safety-valve be tampered 
with, as any moving of the safety-valve under such cir- 
cumstances would have a tendency to cause violent agita- 
tion or foaming of the water over the hot plates, which 
would have the effect of generating more steam than the 
Safety-valve could discharge, and most likely result in an 
explosion. 

Every boiler should be furnished with a safety-valve of 
sufficient capacity to prevent the steam from getting to a 
higher pressure than that considered safe, and the length 
of the lever should be as short as possible, in order that 
the pressure may not be increased with the same weight. 

The safety-valve should always be moved before the 
fire is started to get up steam, in order to ascertain if it is 
in good working order. It should also be raised whenever 
the boiler is being filled with cold water, so as to allow the 
air to escape, as air has a tendency to retard the influx 
of the water, and also to occupy the steam room when 



368 HAND-BOOK OF LAND AND MARINE ENGINES. 

steam is»raised. Air also interferes with the uniform ex- 
pansion of the boiler. The safety-valve should be kept 
open until the steam commences to escape. 

All new boilers should be thoroughly examined before 
being filled with water, in order to ascertain if there are 
any tools, wood, lamps, greasy waste, etc., left behind by 
the boiler-makers, that would be liable to be carried into 
the connections, or cause the boiler to foam. 

In getting up steam in boilers just filled with cold water, 
or that have been out of use for sometime, the fire should 
be allowed to burn moderately at first, in order to admit 
of the slow and uniform expansion of all parts of the 
boiler ; as, when the fire is allowed to burn rapidly from 
the first start, some parts become expanded to their utmost 
limits, while others are as yet nearly cold, thereby expos- 
ing the boiler to those fearful strains induced by unequal 
expansion and contraction, resulting, as they always do, in 
leakage, fracture, and sagging of the shell and flues. 

In all cases, the engineer, or the person having charge, 
should ascertain with certainty the height of the water in 
the boiler before opening the draught or starting the fire, as 
any neglect to do so might be productive of great danger 
and inconvenience. 

When boilers are laid up, or out of use, even if it be 
for a few days, they should be opened, cleaned, and thor- 
oughly examined, in order to ascertain if any of the stays 
or braces have become loose or slack, or disconnected. 
Before being closed up, all gaskets for man- and hand- 
holes, and grummets for mud-holes, should be painted with 
a coating of black lead, in order to protect their seats 
from deterioration, induced by the chemical action of the 
sulphur in the gum packing, now so universally used for 
the joints of steam-boilers. 

In view of tjie above enumerated evils that so silently 



HAND-BOOK OF LAND AND MARINE ENGINES. 869 

and persistently affect the durability of steam-boilers, the 
question might naturally be asked, " What guarantee of 
safety have steam users and the public against disastrous 
explosions ? " The answer would be, that safety does not 
depend so much on the strength of boilers as it does on 
their care and management, from the fact that a thorough 
knowledge of their condition enables intelligent engineers 
to avoid numerous causes and remedy many defects that 
would ultimately lead to destruction. 

HEATING SURFACE. 

The evaporative power of a boiler mainly depends 
upon the efficiency of its heating surface, whose duty it is 
to transfer the heat from the products of combustion with- 
out to the water within. 

The heat is communicated to the transmitting surface 
in two different ways, — by radiation and by contact ; and 
from two or three different hot masses in the furnace, viz., 
the solid incandescent fuel, the flame, and the hot gases 
produced by combustion. Beyond the furnace-bridge or 
tube-plate, the heat is imparted by contact and radiation 
from tl^e flame and gases only. 

The amount of heat transmitted by radiation from one 
body to another diminishes as the square of the distance 
between the bodies increases. The effect on any surface is 
also diminished by any increase in the inclination at which 
the rays fall upon it. 

The radiation from solid incandescent fuel is greater 
than from flame, whilst transparent hot gases scarcely 
radiate any heat at all. The more intense the contact 
heat of the flame by thorough mixture with the air, the 
less is the heat by radiation. 

Conduction is the transfer of heat either between the 
particles of the same body, or between the parts of dif- 

Y 



870 HAND-BOOK OF LAND AND MARINE ENGINES. 

» 

ferent bodies in contact, and it is distinguished respectively 
as internal and external conduction. The rate at which 
the former takes place in metal plates is very much 
greater than the latter, where the heat passes from the hot 
mass to the plates, and from these again to the water. 

The efficiency of any heating surface may be defined 
as the proportion borne by the amount of heat it transmits 
to the whole amount available for transmission. 

Aflat, horizontal surface, not too far above the layer of 
fuel, is usually considered to be the most favorable for 
raising steam. By being made concave to the fire, it has, 
however, the further advantages of being still better 
adapted for receiving the radiant heat ; of facilitating the 
access of fresh supplies of water to replace the heated 
ascending particles, and thereby promoting the circula- 
tion ; of boiling off the matters deposited from the water, 
and so preventing incrustation ; and of being stronger, 
and in some cases more durable. 

Next in efficiency to the flat surface with the water 
above, comes the sloping surface surrounding the fire, 
which is superior to one in a vertical position, as it 
receives the rays of heat at a more favorable angle, and 
allows the steam bubbles to escape more freely. The 
value of horizontal surfaces beneath the fire is not worthy 
of consideration as heating surface. 

In externally fired boilers the heating surface is usually 
convex to the fire. This is, by many, regarded as inferior 
to a concave surface, probably because it is not so well 
adapted for directly receiving the radiant heat from the 
fire, and does not^fppear to ofl^er an equal facility for 
circulation. The results obtained from this description 
of surface in actual work do not appear to verify this con- 
clusion. The inferior evaporative power usually alleged 
of the ordinary externally fired boiler is, in a great 
measure, due to the waste of heat in the furnace. 



HAXD-BOOK OF LAXD AND MARINE ENGINES. 371 

RULES FOR FINDING THE HEATING SURFACE OF 
STEAM-BOILERS. 

Rule for Locomotive op Fire-box Boilers. — Multiply 
the length of the furnace-plates in inches by their height 
above the grate in inches ; multiply the width of *the ends 
in inches by their height in inches ; also, the length of the 
crown-sheet in inches by its width in inches ; multiply 
the combined circumference of all the tubes in inches by 
their length in inches ; from the sum of the four products 
subtract the combined area of all the tubes and the fire- 
door ; divide the remainder by 144, and the quotient will 
be the number of square feet of heating surface. 

Rule fop Flue Boilers. — Multiply | of the circum- 
ference of the shell in inches by its length in inches ; 
multiply the combined circumference of all the flues in . 
inches by their length in inches; divide the sum of these 
two products by 144, and the quotient will be the number 
of square feet of heating surface. 

Rule fop Cylindep Boileps. — Multiply! of the circum- 
ference in inches by its length in inches; add to this 
product the area of one end ; divide this sum by 144, and 
the quotient will be the number of square feet of heating 
surface. 

Rule fop Tubulap Boileps. — Multiply | of the circum- 
ference of the shell in inches by its length in inches ; multi- 
ply the combined circumference of all the tubes by their 
length in inches. To the sum of these two products add | 
the area of both tube-sheets ; from this sum subtract twice 
the combined area of all the tubes ; mvide the remainder 
by 144, and the quotient will be the number of square feet 
of heating surface. 



372 HAND-BOOK OF LAND AND MARINE ENGINES. 

EVAPORATIVE EFFICIENCY OF BOILERS. 

The evaporative efficiency of a given amount of heat- 
ing surface depends upon the time allowed for the trans- 
mission of heat through it, or for the contact of the hot 
gases. The greater their velocity, the less time they have 
to impart their heat to the plates or tubes where the 
length of the surface is constant. The velocity through a 
tube may be increased either by reducing its area, the 
total quantity of gases passing through remaining con- 
stant, or by increasing their draught, and so causing a 
greater amount of gases to pass through in a given time, 
the area of the tube remaining unaltered. 

When the heating surface consists chiefly of tubes, as 
in the locomotive type of boiler, the collective area of the 
tubes may be diminished without decreasing the extent of 
heating surface, since the sectional area varies as the 
square of the diameter, whilst the surface measured by the 
circumference diminishes simply as the diameter. With 
the gases passing at the same velocity through two tubes 
whose diameters are as 1 : 2, the latter will be traversed in 
a given time by four times the quantity of gases, and will 
have only twice the surface to absorb the heat. 

Therefore, to obtain the same evaporative economy as in 
the small tube, we must double the length of the largar, or, 
generally speaking, the proportion between diameter and 
length of a tube is constant for the same evaporative 
efficiency. 

When an increased quantity of gases of the same density 
pass through a tube in a given time, although there will 
be a greater absorption of heat, there will still be a loss 
by the increased amount of heat remaining in the escap- 
ing gases ; and in order to preserve the same economy, or 
in order that the heat of .the escaping gases shall remain 
constant, the length of the tube must be increased in 



HAXD BOOK OF LAND AND MARINE ENGINES. 373 

proportion to the increased quantity of gases passed 
through. 

When we consider the heat to be imparted to the tube 
surface by radiation, which, however slight, is probably 
the principal mode of transfer in vertical and other long 
tubes, where the convection among the particles of gas 
cannot be supposed to take place to any great extent, we 
n\ay assume the heat to be concentrated in the axis of the 
tube, whence we find the quantity of heat received in a 
given time by the surface from radiation will be inversely 
as the square of the diameter. 

By doubling the diameter we shall have four times the 
quantity of gases passed through, and the quantity of heat 
received in a given time will be only one-quarter of ^vhat 
it was before, owing to the increase of distance. 

The surface being, however, twice as great, the absorp- 
tion per unit of length becomes equal to the original. 
Therefore, in order to bring the evaporative efficiency up 
to the original, we must double the length of tube, or 
generally we must increase the heating surface as the 
square of the diameter, in order to obtain the same evapo- 
rative efficiency from radiation when increasing the diam- 
eter of a tube. 

But if we reduce the diameter to one-half, we increase 
the absorbing power fourfold per unit of surface; the 
heating surface being, however, reduced to one-half, the 
evaporative power of the tube will be only doubled, whence 
the tube may be reduced to one-half the original length 
and still retain the same evaporative efficiency, or, the 
length remaining unaltered, the quantity of gases passing 
through should be doubled to maintain the same tempera- 
ture at the escaping end, or, as before, the efficiency of 
each square foot of heating surface increases inversely as 
the square of the diameter. 
32 



374 HAND-BOOK OF LAND AND MARINE ENGINES. 

The evaporative efficiency of a square foot of heating 
surface varies in different classes of boilers, as well as in 
the same boiler under different conditions ; in consequence 
of this there is considerable difficulty in determining the 
precise area of heating surface necessary for the produc- 
tion of a given amount of steam in a given time. 

For a given description of boiler, it is evident the 
evaporative efficiency will mainly depend upon the ratio 
between the quantity of coal consumed and the extent of 
heating surface, as well as the quality of the fuel and the 
manner in which it is burned. 

The easiest method, and consequently the one most 
frequently adopted, is to measure the quantity of water 
by th*e difference of its height in the glass gauge at the 
beginning and end of the experiment. But this method 
is very uncertain, as there can be but little doubt that in 
many boilers the surface of the water is not level, but is 
generally higher over the furnace, where the greatest ebul- 
lition takes places; the difference in the height at any 
time will greatly depend on the intensity of the firing. 

Meters are frequently employed for measuring the quan- 
tity of water that enters a boiler in a given time ; but, like 
all other contrivances resorted to for that purpose, they 
are not always reliable. The only sure method of ascer- 
taining the quantity of water evaporated is by actual meas- 
urement with a cistern or vessel whose cubic contents are 
accurately known. The quantity of water in the boiler 
before and after the trial should be measured at the same 
temperature, which should not exceed 212°, to insure 
accuracy. 

But even when the amount of water introduced, and 
the quantity passed off from the boiler, are accurately ascer- 
tained, there yet remains a doubt as to how much has been 
, actually evaporated, and how much may have passed off 



HAND-BOOK OF LAND AND MARINE ENGINES. 375 

in priming, as there are very few boilers that do not prime 
more or less, and the quantity of water passed off in this 
manner is sometimes very considerable, and often fur- 
nishes boiler-makers, and more particularly manufacturers 
of patent boilers, an opportunity to delude steam users 
with the belief that their boilers are capable of evapora- 
ting 14 or 15 pounds of water to 1 pound of ordinary coal. 
In fact, unless the amount of water passed over with 
the steam by priming, when working under pr(3ssure, can 
be accurately ascertained,' it is utterly impossible to deter-, 
mine the evaporative capacity of the boiler. 

HORSE-POWER OP BOILERS. 

It must be admitted that the manner in which the 
power of a boiler is usually calculated is far from satisfac- 
tory. As it has long been the custom to estimate boilers 
by their real or nominal horse-power, and the nominal 
horse-power of engines is usually based upon the diameter 
of the cylinder, without regard to other conditions, so in 
boilers the nominal standard of power is estimated by their 
size, without regarding the pressure of steam, the efficiency 
of heating surface, size of grate, rate of combustion, qual- 
ity of fuel, etc. 

At the present time, it might be said that there is no 
received rule for estimating the power of a steam-boiler ; 
that is to say, no rule generally recognized by the trade. 
As it has long been a custom in England to estimate the 
horse -power of boilers for stationary enghies by their 
length, regardless of the diameter and other conditions, 
if we turn to marine engines, we find some makers esti- 
mating their power entirely by the grate surface; but 
while one maker divides his grate area by '8 and calls 
the result the horse-power, another uses '75, and another 
uses -5. Thus, a boiler with 100 square feet of grate sur- 



376 HAND-BOOK OF LAND AND MARINE ENGINES. 

face maybe called 125-, 133-, or 200-horse power. Others, 
again, neglect grate surface altogether and go by heating 
surface, and anything between 12 and 25 feet is said by 
different makers to represent a horse-power. 

In view of the foregoing facts, it is very desirable that, 
in purchasing boilers, some understanding should be estab- 
lished as to the quantity of steam they are capable of fur- 
nishing in a given time. 

An idea has been very generally entertained by boiler- 
makers and boiler dealers that it would be impossible to 
lay down any rule that would apply to all classes and 
varieties of boilers ; but this seems quite improbable, as 
there should be no great difficulty in dividing boilers into 
different classes, and establishing, as a rule, the number of 
square feet of heating surface, steam room, water space, 
and grate surface that would form a standard of horse- 
power for each class. 

And although it might be somewhat difficult to estab- 
lish a standard that would apply with strict accuracy to 
all classes of boilers, still it might be made approxi- 
mately so. 

Certain vague notions have long existed among engi- 
neers and steam users that, in adjusting the dimensions of 
steam-boilers, it is better to have them larger than is 
absolutely necessary, consequently, it has grown into a 
custom to recommend a 15-horse power boiler for a 10- 
horse power engine, a 25-horse power boiler for a 20-horse 
power engine, and so on. 

This pule works well for the seller, but it does not 
always work both ways, as boiler-makers very often de- 
ceive purchasers in the extent of heating surface that they 
ought to receive, such misrepresentations giving rise to 
general distrust, disappointment, and dissatisfaction be- 
tween manufacturers and purchasers. It seems rather 



HAND-BOOK OF LAND AND MARINE ENGINES. 377 

singular that all the ordinary methods of trade should be 
changed when the question becomes one of the purchase 
or sale of a steam-boiler. 

The rule most common in use In this country, if it 
might be called a rule, for determining the horse-power 
of steam-boilers, is to estimate the entire heating surface, 
and give an allowance for a horse-power; for cylinder 
boilers, 14 square feet of heating surface, and 1 square 
foot of grate surface; for flue boilers, 15 square feet of 
heating surface, and | of a square foot of grate surface ; 
and for tubular boilers, 15 to 16 square feet of heating 
surface, and J of a square foot of grate surface. 

A more liberal allowance of grate surface for the flue 
and tubular boilers would give more satisfactory results, 
as, when the grate surface is limited, the fuel has neces- 
sarily to be exposed to a sharp draught, which induces a 
great loss of the heated gases, as they are carried into the 
chimney without having sufficient time to impart their 
heat to the flues and tubes. 



EXAMPLE. 

Diameter of boiler, 48 inches. 
Length " " 11 feet. 
46 3-inch tubes. 

3 )1507968 circumference of shell. 

50-2656 
2 



100-5312 

132 length in inches. 

2010624 
3015936 
1005312 



13270*1184 sq. in. heating surface in shell. 
32^ 



378 HAND-BOOK OF LAND AND MAKINE ENGINES. 

9*4248 circumference of 1 tube. 



565488 
376992 

433-5408 
132 

8670816 
13006224 
43354 08 

57227*3856 sq. in. heating surface in tubes. 
3) 1809*5616 area of 1 tube-sheet. 
603-1872 
2 

1206-3744 
2 



2412*7488 sq. in. heating surface in tube-sheets. 
7*0686 area of 1 tube. 
46 



424116 

282744 



325*1556 area of tubes. 

2 



650-3112 
13270-1184 
57227*3856 
2412*7488 
72910*2528 
650*3112 



144)72259*94'16 total heating surface in sq. in. 
16)501*8 sq. ft. of heating surface. 
31* horse-power. 

Grate surface required, 15^ square feet. 

FIRING. 
Firing, like engineerirrg, ought to be recognized as a 
profession, and none but intelligent men, who can appre- 
ciate the importance of their position, should be placed in 



HAND-BOOK OF LAND AND MARINE ENGINES. 379 

charge of the coal pile ; as it is a well-known fact that 
when the engineer has done all he can to attain economy 
in the steam-engine, much of the result still remains in 
the hands of the fireman. 

The use of a more improved class of steam-engines 
involves the necessity of employing more skilful and 
careful attendants ; not that the work is more difficult, as 
less coal has to be thrown into the furnace, but because a 
careless or unskilful fireman can counteract all the in- 
genuity displayed in the improvement, construction, and 
management of the engine. 

Consequently, every engineer should be required to pre- 
pare himself for the duties of his profession by com- 
mencing as a fireman ; otherwise, how can he be expected 
to be able to instruct his fireman in the manner of firing 
best calculated to insure the most satisfactory and eco- 
nomical results? 

Clean grate-bars, with an even distribution of the fuel 
in the furnace, the exercise of judgment in the quantity 
of air admitted, and the regulation of the draught, are the 
main points to be attended to ; and although they require 
the exercise of skill and intelligence, they cannot be said 
to involve an unreasonable amount of either labor or 
vigilance. 

Even with the best coal and most careful firing, a 
quantity of the coal falls through the fire-bars either as 
unburnt coal or ashes. Another portion goes up the 
chimney, unconsumed, in the form of smoke and soot ; and 
a further quantity, half consumed, in the form of carbonic 
oxide. The loss from these causes may amount to from 
2 to 20 per cent. It all arises from wrongly con- 
structed furnaces and bad firing, and can nearly all be 
avoided. 

Most coal contains a greater or less quantity of moist- 



380 HAND-BOOK OF LAND AND MARINE ENGINES. 

ure, and the evaporation of this moisture causes the first 
loss of heat. Kadiation from the furnace causes a further 
loss. But the great causes of loss are the admission into 
the furnace of a large quantity of useless air and inert 
gases, and the escape of these, with the actual products 
of combustion, up the chimney, at a very much higher 
temperature than that at which they entered the furnace. 

Aip is composed of about one-third oxygen and two- 
thirds nitrogen. The oxygen only is required to effect 
the combustion of the fuel, and the useless nitrogen merely 
abstracts heat from the combustibles, and lowers the 
temperature of the furnace. About 12 pounds of air 
contain sufficient oxygen to effect the combustion of 1 
pound of coal, but, owing to the difficulty of bringing the 
carbon into contact with the oxygen, the quantity actually 
required to pass through the furnace is from 18 to 24 
pounds of air per pound of coal burnt. The surplus air 
passes out unburnt, and its presence in the furnace lowers 
the temperature subsisting there, and abstracts a portion 
of the heat generated. 

As the whole of the aip enters the furnace at about 60° 
Fah., and the unconsumed air and products of combus- 
tion leave the flues at from 400° Fah. to 800° Fah., the 
total loss from these causes is from 20 to 50 per cent. 
Each pound of good coal burnt is theoretically capable 
of evaporating about 15 pounds of water; in good practice 
it evaporates but 9 or 10 pounds, and in ordinary practice 
but 6 or 8 pounds of water. 

There are difficulties in the way of abstracting all the 
heat from the furnace gases ; first, because, with natural or 
chimney draught, the gases require to pass into the chimney 
at not less than 500° Fah., in order to maintain the 
draught,; and secondly, because the transmission of heat 
from the gases to the water, when the difference of their 



HAND-BOOK OF LAND AND MARINE ENGINES. 381 

temperatures is small, is so slow that an enormous exten- 
sion of the surface in contact with them becomes necessary 
in order to effect it. 

But by having energetic combustion and a high tempera- 
ture in the furnace, the quantity of air actually required 
may be much reduced; by suitable arrangements for 
admitting air and feeding coal into the furnace, the 
proportions of each may be suitably adjusted to each 
other ; and by a liberal allowance of properly disposed 
heating surface, the temperature of the reduced quantity 
of furnace gases may be reduced to that simply necessary 
to produce a draught in a furnace with natural draught, 
or to about 400^ Fah., or less, in a furnace where the 
draught is obtained from a steam jet or fan. 

There have not been, heretofore, that attention and 
thought devoted to the examination of the subject of the 
economy of fuel which the magnitude of the interest in- 
volved and its importance in a national point of view 
render it worthy of. The saving of one pound of water 
per horse-power per hour for ten hours a day, providing 
the engine is 100 -horse power, and assuming that the 
boiler evaporates 7 pounds of water per pound of coal, 
would make a saving of 1000 pounds of water per day, 
which would require the consumption of 143 pounds of coal 
per day, or 22^ tons a year, the cost of which would be, 
at the ordinary price of coal, over $125. 

The methods most in vogue for the consumption of all 
kinds of fuel are those which gradually developed them- 
selves, as necessity dictated, to the untutored intellect of 
uncultivated men, and which, however creditable to the 
men that devised them, inasmuch as they availed them- 
selves of all the sources of information ivithin their reach, 
are nevertheless a reproach to the more advanced knowl- 
edge of physical and mechanical science enjoyed by the 
present generation. 



382 HAND-BOOK OF LAND AND MARINE ENGINES. 

INSTRUCTIONS FOR FIRING. 

In estimating the relative merits of different steam- 
engines, it is generally assumed that the fuel is burned 
under conditions with which the men who supply coal to 
the furnaces have nothing whatever to do, — in short, that 
any man who can throw coal on a fire and keep his bars 
clean must be as good as any other man who can do 
apparently the same thing. 

But this conclusion is totally erroneous, as it is within 
the experience of nearly every engineer and steam user 
that many engines now in operation throughout the 
country consume twice as much fuel, per horse-power, 
as is required in those that are more economically 
managed. 

When a boiler is of sufficient capacity to generate the 
necessary amount of steam without urging the fires, it 
will be found most advantageous to carry a thick bed of 
coal on the grates, as, when the coal can be burned in 
large quantities and with a moderate draught, the heat is 
more generally utilized than if the^ coal is burned in 
small quantities and with a sharp draught. 

Fop stationary boilers the fuel should not be less than 
from three to four inches thick on the grate. For marine 
boilers, if anthracite coal be used, from 5 to 6 ; if bitumi- 
nous, from 6 to 8 inches. Of course, the thickness of the 
fire must be governed by the character of the fuel and 
quantity of steam required. 

Before starting a fresh fire in the furnace, a thin layer 
of coal should be scattered over the grate ; most of the 
kindling, whether shavings, oily-waste, or paper, should be 
placed on the ends of the bars next the door, and then 
covered with a uniform layer of wood. This is a necessary 
precaution, as, when the fuel fails to ignite at the front at 



HAND-BOOK OF LAND AND MARINE ENGINES. 383 

first, it generally takes a long time before the fire burns 
through. 

When the coal is in large lumps, so that the spaces 
between them are of considerable size, the depth may be 
greater than where the coal is small and lies compactly ; 
and where the draught is very strong, so that the air passes 
with great velocity over and through the fuel, there is not 
time for the carbonic acid to combine with and carry off 
the products of combustion, and consequently a bed of 
greater depth may with propriety be used. 

When very large coal is used, it will be found of im- 
mense advantage to mix it with some small coal ; more 
particularly so, when the draught is strong, as such an ar- 
rangement forms a resisting barrier to the currents of cold 
air that would otherwise pass through the interstices 
between the lumps, and render the combustion more 
perfect. 

When an increasing quantity of steam is wanted, the 
average thickness or quantity of fuel on the grate must 
not be increased, but rather diminished, and supplied in 
smaller quantities and more frequently. As soon, how- 
ever, as the supply of steam exceeds the demand, the coal 
may again be supplied in larger quantities at a time. 

In firing up, the coal should be scattered evenly over 
the grate, but thinner at the front near the dead-plate 
than at the middle or back, and no portion of the grate 
should ever be left uncovered. 

When it becomes necessary to replenish the fire, it 
should be done as quickly as possible, as, when the damper 
and the fire-door are both open at the same time, the 
current of cold air passing through the furnace above the 
fuel not only reduces the temperature in the furnace, but 
has a tendency to injure the boiler. 

There should in all cases be ample fire in the furnace, 



384 HAND-BOOK OF LAND AND MARINE ENGINES. 

an extra quantity of water in the boiler, and a full head 
of steam, before any attempt is made to clean the fire; 
then the damper should be opened to its full limit, in 
order that the heated gases and dust may pass into the 
flue ; and, if there be more than one fire, one only should 
be cleaned at a time, and allowed to become thoroughly 
kindled before the next one is cleaned. 

The fire should never be allowed to become low 
for the purpose of making it more easy to clean, as, in 
consequence of the small quantity of fire in the furnace 
after cleaning, it would have a tendency to go nearly out, 
which is often attended with great loss and inconvenience. 
It is always best to have a good fire, then close the damper 
and open the furnace door, in order to take the white glare 
ofi* the fire before commencing to clean it ; the damper 
should then be reopened to its full extent and all the live 
fire pushed back to the bridge, without disturbing any of 
the ashes or cinders ; the latter should then be drawn out, 
and the fire that was pushed back, drawn forward to one 
side, and the ashes and cinders that remain near the 
bridge removed. The fire should then be distributed 
evenly over the grate, all the cinde»s and clinkers that 
remain picked out, and the fire covered with a thin layer 
of fresh coal, care being taken to waste none of the com- 
bustible fuel. 

Before commencing to clean the fire, it is always advis- 
able for the fireman to place a piece of scantling a short 
distance in front of the furnace, in order to protect his 
feet from the hot cinders as they fall out. 

In cleaning the fires of locomotive, marine, or other 
fire-box boilers, water should not be thrown in the ash-pit, 
as the lye formed from the wet ashes has a tendency to 
corrode and destroy the fire-box and water-legs. 

The fire should never be disturbed so long as any 



HAI^D-BOOK OF LAND AND MARINE ENGINES. 385 

light shines through the grate into the ash-pit, unless the 
boiler fails to furnish the necessary amount of steam. Even 
then it is better, if anthracite coal be the fuel, to shed out 
the ashes from the bottom through the grate with a thin 
hooked poker; but if bituminous coal be used, it requires 
frequent breaking up, in order to allow the air to intensify 
the combustion. When broken up, it should always be 
pushed back to\vard the bridge, and the fresh fuel supplied 
in the front and allowed to coke. The smaller the quan- 
tity supplied at a time, and the more attention paid to its 
distribution and regulation, the more perfect will be the 
combustion and the more intense the heat. 

If, from neglect or any other cause, the fire should 
become very low or the grate partly stripped, it should 
not be poked or disturbed, as that would have a tendency 
to put it entirely out ; but wood, shavings, saw-dust, greasy 
waste, or some other combustible substance, should be 
thrown on the bare places, and, after being covered with 
a thin layer of coal, the damper opened to its full extent. 

If strict attention be paid to the regulation of the 
furnace, and coal applied to only one side of the fire at a 
time, nearly all the smoke can be consumed and quite a 
saving in fuel efiected. Fresh coal, should never be sup- 
plied except when absolutely necessary, and even then 
only in small quantities and at such places as are most 
aSected by the draught, as it is a common error, with inex- 
perienced firemen, to continually supply coal to the furnace, 
which eventually becomes choked, and the combustion of 
the fuel rendered imperfect. 

The regulation of the draught should receive particular 
attention, as air costs nothing, while fuel is quite expensive; 
therefore none of the latter should be allowed to pass out 
of the furnace without being fully utilized. The ash-pit 
and front of the furnace should at all times be kept free 
33 Z 



886 HAND-BOOK OF LAND AND MARINE ENGINES. 

from dirt, ashes, and cinders, as such accumulations have 
not only the effect of diminishing the cubic contents of the 
space under the furnace, but also of obstructing the free 
flow of air through the grate-bars, so essential to the per- 
fect combustion of the fuel. 

It is a well-known fact, that much of the waste attributed 
to the steam-engine occurs in the furnace, and while some 
of it may be unavoidable, a great portion of it, neverthe- 
less, is due to bad firing, which is the result of ignorance, 
carelessnes, or inattention. 

RULES FOR FINDING THE QUANTITY OF WATER 
BOILERS AND OTHER CYLINDRICAL VESSELS 
ARE CAPABLE OF CONTAINING. 

Rule for Cylinder Boilers. — Multiply the area of. the 
head in inches by the length in inches, and divide the pro- 
duct by 1728 ; the quotient will be the number of cubic 
feet of water the boiler will contain. 

EXAMPLE. 

Diameter of head, 36 inches. 

Area '' '* 1017-87 '* 

Length of boiler, 20 feet, or 240 inches. 

1017-87 

240 

^ / 

4071480 
203674 ^J^ 



1728 )244288-80 'J^ 

141-37 cubic feet. " ^' 

Rule for Flue Boilers. — Multiply the area of head in 
inches by the length of the shell in inches ; multiply the 
combined area of the flues in inches by their length in 
inches ; subtract this product from the first and divide the 



HAND-BOOK OF LAND AND MARINE ENGINES. 387 

remainder by 1728 ; the quotient will be the number of 
cubic feet of water the boiler will contain. 

fiule.— To find theRequisite Quantity of Water for a Steam- 
loiler. — Add 15 to the pressure of steam per square inch; 
divide the sum by 18 ; multiply the quotient by '24 ; the 
product will be the quantity in U. S. gallons per minute 
for each horse-power. 

[{\x\b,—To find the Required Height of a Column of Water 
to supply a Steam-boiler against any given Pressure of Steam, 
— Multiply the boiler pressure in pounds per square inch 
by 2-5 ; the product will be the required height in feet 
above the surface of the water in the boiler. 

Another RulOa — To find the Requisite Quantity of Water 
for a steam-boiler,— -When the number of pounds of coal 
consumed per hour can be ascertained, divide it by 7*5, 
and the quotient will be the required quantity of water in 
cubic feet per hour. 

LONGITUDINAL AND CURVILINEAR STRAINS. 

The force tending to rupture a oylincler along the 
curved sides depends upon the diameter of the cylinder 
and pressure of steam ; and we may regard, hence, the 
total pressure sustained by the sides to be equal to the di- 
ameter X pressure per unit of surface X length of cyl- 
inder, neglecting any support derivable from the heads, 
which, in practice, depends on the length. 

It must be understood that the strain on a boiler sub- 
jected to internal pressure transversely, is exactly double 
what it is longitudinally, or in other words, the strain on 
the longitudinal seams is double that on the curvilinear. 
And no matter what the diameter of a boiler may be, the 
transverse pressure tending to tear it asunder will always 
be double the pressure exerted on the curvilinear seams. 



388 HAND-BOOK OF LAND AND MARINE ENGINES. 

RULES. 

Rule joT finding Safe Working Pressure of Iron Boilers, 
— Multiply the thickuess of the iron by '56 if single riveted, 
and '70 if double riveted ; multiply this product by 10,000 
(safe load) ; then divide this last product by the external 
radius (less thickness of iron) : the quotient will be the 
safe working pressure in pounds per square inch. 

EXAMPLE. 
Diameter of boiler... 42 inches. 



2)42 

21 external radius. 
•375 



20*625 internal radius. 
Thickness of iron | = "375 

•56 single riveted. 
2250 

1875 



•21000 

10000 safe load. 



20-625) 2100-00000 

101*81 pounds safe working press. 

In the above rule, 50,000 pounds per square inch are 
taken as the tensile strength of boiler iron, and one-fifth 
of that, or 10,000, as the safe load. Hence five times the 
safe working pressure, or 50,000 pounds, would be the burst- 
ing pressure. 

Rule for finding the Safe Working Pressure of Steel Boilers. 
— Multiply the thickness of steel by '56 if single riveted, 
and '70 if double riveted ; multiply this product by 16,000 
(safe load) ; then divide this last product by the external 
radius (less thickness of steel) : the quotient will be the 
safe working pressure in pounds per square inch. 



HAND-BOOK OF LAND AND MARINE ENGINES. 389 

EXAMPLE. 

Diameter of boiler 44 inches. 

Thickness of steel J inch. 

2)44 
22 external radius. 
'25 
21'75 internal radius. 
Thickness of steel ^ =^ '25 

•70 double riveted. 
1750 
16000 

1050000 
175 

21'75) 2800-000 

128*73 safe working pressure. 

80,000 being taken, in the above rule, as the tensile strength 

of steel, and one-fifth of that, or 16,000, as the safe load. 

Hence 80,000 would be the bursting pressure. 

Rule for finding the Aggregate Strain caused by the Press- 

ure of Steam on the Shells of Steam-boilers. — Multiply the 

circumference in inches by the length in inches ; multiply 

this product by the pressure in pounds per square inch. 

The result will be the aggregate pressure on the shell of 

the boiler. 

EXAMPLE. 

Diameter of boiler 42 inches. 

Circumference of boiler 131*9472 " 

Length " 10 ft, or 120 ^' 

Pressure " 125 pounds. 

131-9472 X 120 X 125 = 1,979,208 pounds -- 2000 = 989 tons. 

EXPLANATION OP TABLES OP BOILER PRESSURES 
ON POLLOWING PAGES. 

The figures |, 00, 0, 1, etc., in the horizontal column on 

the top of the tables on pages 390, 391, 392, 393, 394, 395, 

396, and 397, represent the number of the iron or steel. 
33* 



390 



HAND-BOOK OF LAND AND MARINE ENGINES. 



The decimals in the second horizontal column are equal 

to the fractional parts of inches in the third column. The 

vertical column on the left-hand side represents the 

diameter of the boiler in inches. All the other columns 

represent pounds pressure. 

Example. — 24-inch diameter, f steel, 289*03 pounds per 

square inch. 

TABLE 

OF SAFE INTERNAIi PRESSURES FOR IRON BOILERS. 



Birmingham Wire I 


f 


00 





1 


2 


Gauge. 




Thickness of Ironi 


.375 

1 


.358 
1 Scant. 


.340 


.300 


.284 




Dia. 


lbs. per 


lbs. j>eT 


lbs. per 


lbs. per 


lbs. per 




In. 


sq. in. 


sq. in. 


sq. in. 


sq. in. 


sq. m. 


External 


24 


180.65 


172.20 


163.29 


143.59 


135.75 


Diameter. 


26 


166.34 


158.58 


150.39 


132.28 


125.08 




28 


154.13 


146.96 


139.38 


122.63 


115.95 




30 


143.59 


136.92 


129.88 


114.29 


108.07 




32 


134.40 


128.17 


121.58 


107.01 


101.20 




34 


126.31 


120.47 


114.29 


100.60 


95.14 




86 


119.15 


113.64 


107.81 


94.92 


89.77 




38 


112.75 


107.54 


102.04 


89.84 


84.98 




40 


107.01 


102.07 


96.85 


85.28 


80.67 




42 


101.81 


97.12 


92.11 


81.16 


76.77 


Longitudinal 


44 


97.11 


92.63 


87.90 


77.42 


73.24 


Seams, 


46 


92.82 


88.54 


84.02 


74.01 


70.01 


Sin^e 


48 


88.89 


84.80 


80.47 


70.89 


67.06 


Kiveted. 


50 


85.28 


81.36 


77.21 


68.02 


64.35 




52 


81.95 


78.18 


• 74.20 


65.37 


61.84 




54 


78.87 


75.25 


71.42 


62.92 


59.53 




56 


76.02 


72.53 


68.84 


60.65 


57.38 




58 


73.36 


70.00 


66.43 


58.54 


55.38 




60 


70.89 


67.63 


64.19 


56.57 


53.52 




62 


68.57 


65.43 


62.10 


54.72 


51.78 




64 


66.40 


63.36 


60.14 


58.00 


50.15 




m 


64.37 


61.42 


58.30 


51.33 


48.61 




68 


62.45 


59.59 


56.57 


49.85 


47.17 




70 


60.65 


57.87 


54.93 


48.41 


45.81 




72 


58.95 


56.25 


53.39 


47.06 


44.53 




74 


57.34 


54.71 


51.94 


45.78 


43.32 




76 


55.81 


53.26 


50.56 


44.56 


42.17 




78 


54.37 


51.88 


49.25 


43.41 


41.08 




80 


53.00 


50.57 


48.01 


42.32 


40.04 , 



HAND-BOOK OF LAND AND MARINE ENGINES. 



391 



T A B L 'Ei'^iConiimied) 
OF SAFE INTERNAL PRESSURES FOR IRON BOILERS. 



Birmingham 
Wire Gauge. 


3 


4 


5 


6 


7 


8 


Thickness 


.^59 


.238 


.220 


.203 


.180 


.165 


of Iron. 


i Full. 


} Scant. 


A 


/^Full. 


g^Scant 


A Full. 




Dia. 


lbs. per 


lbs. per 


lbs. per 


lbs. per 


lbs. per 


lbs. per 




In. 


sq. in. 


sq. in. 


sq. m. 


sq. in. 


sq. in. 


sq. in. 


External 


24 


123.53 


113.31 


104.58 


96.36 


85.28 


78.07 


Diameter. 


26 


113.84 


104.44 


96.40 


88.83 


78.63 


71.99 




28 


105.55 


96.85 


89.40 


82.39 


72.94 


66.79 




30 


98.39 


90.29 


83.36 


76.83 


68.02 


62.29 




32 


92.14 


84.56 


78.07 


71.96 


63.72 


58.35 




34 


86.64 


79.51 


73.42 


67.68 


59.93 


54.89 




36 


81.75 


75.04 


69.29 


63.88 


56.57 


51.81 




38 


77.39 


71.04 


65.60 


60.48 


53.56 


49.06 




40 


73.47 


67.44 


62.29 


57.42 


50.86 


46.58 




42 


69.93 


64.19 


59.29 


54.66 


48.41 


44.35 




44 


66.71 


61.24 


56.57 


52.15 


46.20 


42.32 


Long. 


46 


63.78 


58.55 


54.08 


49.87 


44.17 


40.46 


Seams, 


48 


61.09 


56.09 


51.81 


47.77 


42.32 


38.77 


Single 


60 


58.62 


53.82 


49.72 


45.84 


40.61 


37.21 


Eiveted. 


52 


56.35 


51.74 


47.79 


44.07 


39.04 


35.77 




54 


54.24 


49.80 


46.00 


42.42 


37.58 


34.43 




56 


52.28 


48.01 


44.35 


40.90 


36.23 


33.20 


.-, 


58 


50.46 


46.34 


42.81 


39.48 


34.98 


32.04 


f: 


60 


48.77 


44.78 


41.37 


38.15 


33.80 


30.97 




62 


47.18 


43.33 


40.03 


36.91 


32.71 


29.97 




64 


45.69 


41.96 


38.77 


35.75 


31.68 


29.02 




m 


44.30 


40.68 


37.58 


34.66 


30.71 


28.14 




68 


42.99 


39.48 


36.47 


33.64 


29.80 


27.31 




70 


41.75 


38.34 


35.42 


32.67 


28.95 


26.53 


If 


72 


40.58 


37.27 


34.43 


31.76 


28.14 


25.78 


'• 


74 


39.48 


36.25 


33.50 


30.89 


27.38 


25.08 




76 


38.43 


35.29 


32.61 


30.08 


26.65 


24.42 




78 


37.44 


34.38 


31.77 


29.30 


25.96 


23.79 




80 


36.49 


33.52 


30.97 


28.56 


25.31 


23.20 



B92 



HAND-BOOK OF LAND AND MARINE ENGINES. 



TABLE — (Continued) 

OF SAFE INTERNAL PRESSURES FOR IRON BOILERS. 



Birmingham Wire 
Gauge. 


1 


00 





1 


2 


Thickness of Iron. 


.375 

1 


.358 
1 Scant. 


^^ 

.340 

a 


.300 


.284 










Dia. 


lbs. per 


lbs. per 


lbs. per 


lbs. per 


lbs. per 




In. 


sq. in. 


sq. m. 


sq. in. 


sq. m. 


sq. in. 


External 


24 


225.81 


215.26 


204.12 


179.49 


169.67 


Diameter. 


26 


207.93 


198,23 


187.91 


165.35 


156.34 




28 


192.66 


183.70 


174.23 


153.28 


144.94 




30 


179.49 


171.15 


162.35 


142.86 


135.09 




32 


168.00 


160.21 


151.98 


133.76 


126.49 




34 


157.89 


150.58 


142.86 


125.75 


118.93 




36 


148.94 


142.05 


134.77 


118.64 


112.21 




38 


140.94 


134.43 


127.55 


112.30 


106.22 




40 


133.76 


127.58 


121.06 


106.60 


100.83 


Longitudinal 


42 


127.27 


121.40 


115.20 


101.45 


95.96 


Seams, 


44 


121.39 


115.79 


109.88 


96.77 


91.55 


Double 


46 


116.02 


110.68 


105.03 


92.51 


87.52 


Kiveted, 


48 


111.11 


106.00 


100.59 


88.61 


83.83 


Curvilinear 


50 


106.19 


101.70 


96,51 


85.02 


80.43 


Seams, 


52 


102.44 


97.73 


92.75 


81.71 


77.33 


Single 


54 


98.59 


94.10 


89.27 


78.69 


74.41 


Eiveted. 


56 


95.02 


90.66 


86.04 


75.81 


71.73 




58 


91.70 


87.49 


83.04 


73.17 


69.23 




60 


88.61 


84.54 


80.24 


70.71 


66.90 




62 


85.71 


81.78 


77.63 


68.40 


64.72 




64 


83.00 


79.17 


75.17 


66.25 


62.68 




66 


80.46 


76.78 


72.87 


64.22 


60.77 




68 


78.07 


74.47 


70.71 


62,31 


58.96 




70 


75.81 


72.34 


68.67 


60.52 


67.26 




72 


73.68 


70.31 


66.74 


58.82 


55.66 




74 


71.67 


68.39 


64.92 


57.22 


54.15 




76 


69.77 


66.60 


63.19 


55.70 


52.77 




78 


67.96 


64.85 


61.56 


54.26 


51.35 




80 


66.25 


63.22 


60.01 


52.90 


60.06 



HAND-BOOK OF LAND AND MARINE ENGINES. 



393 



TABLE- (Continued) 
OF SAFE INTERNAL PRESSURES FOR IRON BOILERS. 



Birmingham 
Wire Gauge. 


3 


4 


5 


6 


7 


8 


Thickness 


.259 


.238 


.220 


.203 


.180 


.165 


of Iron. 


i Full. 


J Scant. 


3V 



lbs. per 


3% Full. 


3%Scant 


/^Full 




Dia. 


lbs. per 


lbs. per 


lbs. pet 


lbs. per 


lbs. per 




In. 


sq. in. 


sq. in. 


sq. in. 


sq. in. 


sq. in. 


sq. in. 


External 


24 


154.42 


141.64 


130.73 


120.45 


106.60 


97.59 


Diameter. 


26 


142.30 


130.54 


120.50 


111.04 


98.21 


89.99 




28 


131.94 


121.06 


111.76 


102.99 


91.17 


83.48 




30 


122.99 


112.86 


104.19 


96.03 


85.02 


77.86 




32 


116.32 


105.70 


97.59 


89.95 


79.65 


72.94 




34 


108.30 


99.39 


91.78 


84.60 


74.91 


68.61 




36 


102.19 


93.80 


86.61 


79.84 


70.71 


64.76 




38 


96.74 


88.80 


82.00 


75.60 


66.95 


61.32 




40 


91.84 


84.30 


77.86 


71.78 


63.57 


58.23 




42 


87.41 


80.24 


74.11 


68.33 


60.52 


55.44 




44 


83.39 


76.56 


70.71 


65.19 


57.75 


52.90 


Long. 


46 


79.72 


73.19 


67.60 


62.33 


55.22 


50.58 


Seams, 


48 


76.37 


70.11 


64.76 


59.71 


52.90 


48.46 


Double 


50 


73.28 


67.28 


62.11 


57.31 


50.77 


46.51 


Kiveted. 


52 


70.43 


64.67 


59.74 


55.08 


48.80 


44.71 


Curvil. 


54 


67.80 


62.25 


57.51 


53.40 


46.98 


43.04 


Seams, 


56 


65.35 


60.01 


65.44 


51.12 


45.29 


41.50 


Single 


58 


63.07 


57.92 


53.51 


49.35 


43.72 


40.06 


Kiveted. 


60 


60.96 


55.98 


51.71 


47.69 


42.25 


38.71 




62 


58.98 


54.16 


50.03 


46.14 


40.88 


37.46 




64 


57.12 


52.45 


48.46 


44.69 


39.60 


36.28 




66 


55.37 


50.85 


46.98 


43.33 


38.39 


35.18 




68 


53.73 


49.35 


45.59 


42.05 


37.26 


34.14 




70 


52.19 


47.93 


44.28 


40.84 


36.19 


33.16 




72 


50.73 


46.59 


43.04 


39.70 


35.18 


32.23 




74 


49.35 


45.32 


41.87 


38.62 


34.22 


31.36 




76 


48.04 


44.11 


40.76 


37.60 


33.32 


30.53 




78 


46.80 


42.98 


39.71 


36.63 


32.46 


29.74 




80 


45.62 


41.90 


38.71 


35.71 


31.64 


28.99 



394 



HAND-BOOK OF LAND AND MARINE ENGINES. 



T A B L lE^i—iCkmtinued) 

OP SAFE INTERNAL PRESSURES FOR STEEL BOILERS. 



Birmingham Wire 


3 


00 





1 


2 


Gauge. 




f 


Thickness of Steel. 


.375 
1 


.358 
f Scant. 


.340 


.300 


.284 




Dia. 


lbs. per 


lbs. per 


lbs. per 


lbs. per 


lbs. per 




In. 


sq. m. 


sq. m. 


sq. ID. 


sq. in. 


sq. in. 


External 


24 


289.03 


275.52 


261.26 


229.74 


217.19 


Diameter. 


26 


266.13 


253.73 


240.31 


211.65 


200.08 




28 


246.66 


235.13 


223.01 


196.20 


185.45 




30 


229.74 


219.00 


207.80 


182.85 


172.99 




32 


215.04 


205.06 


194.15 


171.21 


161.91 




34 


202.10 


192.74 


182.85 


160.95 


152.22 




36 


190.63 


181.82 


172.50 


151.86 


143.23 




38 


180.40 


172.06 


163.25 


143.74 


135.96 


Longitudinal 


40 


171.21 


163.30 


154.95 


136.44 


129.06 


Seams, 


42 


162.90 


155.39 


147.45 


129.85 


122.83 


Single 


44 


155.37 


148.21 


140.66 


123.87 


117.17 


Kiveted. 


46 


148.50 


141.66 


134.43 


118.41 


112.01 




48 


142.22 


135.67 


128.75 


113.41 


107.29 




50 


136.44 


130.17 


123.53 


108.82 


100.03 




52 


131.12 


125.09 


118.72 


104.59 


98.95 




54 


126.19 . 


120.39 


114.26 


100.67 


95.24 




56 


121.62 


116.04 


110.13 


97.03 


91.81 




58 


117.37 


111.99 


106.29 


93.65 


88.61 




60 


113.41 


108.21 


102.71 


90.50 


85.63 




62 


109.71 


104.68 


99.36 


87.55 


82.89 




64 


106.24 


101.37 


96.22 


84.79 


80.23 




66 


102.98 


98.26 


93.27 


82.20 


77.77 




68 


99,92 


95.34 


. 90.32 


79.76 


75.47 




70 


97.03 


92.59 


87.89 


77.43 


73.29 




72 


94.31 


89.99 


85.42 


75.29 


71.24 




74 


91.74 


87.81 


83.09 


73.24 


69.30 




76 


89.30 


85.21 


80.89 


71.29 


67.46 




78 


86.99 


83.01 


78.79 


69.45 


65.72 




80 


84.79 


80.91 


76.81 


67.70 


64.07 

















HAND-BOOK OF LAND AND MARINE ENGINES. 



395 



TABLE — (Continued) 
OF SAFE INTERNAL PRESSURES FOR STEEL BOILERS. 



Birmingham 
Wire Gauge. 


3 


4 


5 


6 


7 


8 


Thickness 


.259 


.238 


.220 


.203 


.180 


.165 


of Steel. 


i Full. 


i Scant. 


A 


A Full. 


Y^Scant 


A Full. 




Dia. 


lbs. per 


lbs. per 


lbs. per 


lbs. per 


lbs. per 


lbs. per 




IiV 


sq. in. 


sq. in. 


sq. in. 


sq. in. 


sq. in. 


sq. in. 


External 


24 


197.63 


181.13 


167.33 


154.18 


136.44 


124.91 


Diameter. 


26 


182.13 


167.09 


154.24 


142.13 


125.80 


115.10 




28 


168.88 


154.95 


143.04 


131.83 


116.70 


106.85 




30 


157.42 


144.45 


133.36 


122.92 


108.82 


99.65 




32 


147.42 


135.29 


124.91 


115.14 


101.94 


93.36 




34 


138.60 


127.22 


117.47 


108.28 


95.88 


87.81 




36 


130.80 


120.05 


110.86 


102.20 


90.50 


82.89 


Long. 


38 


123.82 


113.65 


104.96 


96.76 


85.69 


78.49 


Seams, 


40 


117.55 


107.90 


99.65 


91.81 


81.37 


74.53 


Single 


42 


111.40 


102.71 


94.85 


87.45 


77.46 


70.95 


Kiveted. 


44 


106.71 


97.99 


90.50 


83.44 


73.91 


67.70 




46 


102.04 


93.68 


86.53 


79.78 


70.67 


64.74 




48 


97.74 


89.74 


82.89 


76.43 


67.70 


62.02 




50 


93.07 


86.11 


79.54 


73.35 


64.97 


59.12 




52 


90.15 


82.77 


76.46 


70.50 


62.45 


57.22 




54 


86.78 


79.68 


73.60 


67.87 


60.13 


55.09 




56 


83.65 


76.09 


70.95 


65.43 


57.97 


53.11 




58 


80.74 


74.14 


68.49 


63.16 


55.96 


51.27 




60 


78.02 


71.62 


66.19 


61.07 


54.04 


49.55 




62 


75.49 


69.32 


64.04 


59.06 


52.32 


47.94 




64 


73.11 


67.13 


62.02 


57.20 


50.68 


46.43 




m 


70.88 


65.09 


60.13 


55.45 


49.14 


45.02 




68 


68.77 


63.16 


58.35 


53.52 


47.68 


43.69 




70 


66.79 


61.28 


56.67 


52.27 


46.31 


42.44 




72 


64.92 


59.76 


55.09 


50.81 


45.02 


41.25 




74 


63.16 


58.00 


53.59 


49.43 


43.80 


40.13 




76 


61.48 


56.47 


52.17 


48.12 


42.64 


39.07 




78 


59.90 


55.01 


50.83 


46.88- 


41.54 


38.06 




80 


58.39 


53.63 


49.55 


45.65 


40.50 


37.11 



396 



HAKD-BOOK OF LAND AND MARINE ENGINES. 



T A B Li E — (Continued) 
OF SAFE INTERNAL PRESSURES FOR STEEL BOILERS. 



Birmingham Wire 


f 


00 





1 


2 


Gauge. 


Thickness of Steel. 


.375 

f 


.358 
1 Scant. 


.340 


.300 


.284 




Dia. 


lbs. per 


lbs. per 


lbs. per 


lbs. per 


lbs. per 




In. 


sq. in. 


sq. in. 


sq. m. 


sq. in. 


sq. in. 


External 


24 


361.29 


344.40 


326.58 


287.23 


271.49 


Diameter. 


26 


332.67 


317.24 


300.78 


264.56 


250.14 




28 


308.25 


293.91 


278.77 


237.95 


231.90 




30 


287.18 


273.48 


259.75 


228.57 


216.14 




32 


268.80 


256.34 


243.16 


214.01 


202.39 




34 


252.63 


240.93 


228.57 


201.19 


190.28 




36 


238.24 


227.27 


215.62 


189.83 


179.54 


Longitudinal 


38 


225.50 


215.08 


204.07 


179.67 


169.95 


Seams, 


40 


214.01 


204.13 


193.69 


170.55 


161.28 


Double 


42 


203.63 


194.24 


184.31 


162.31 


153.54 


Riveted. 


44 


194.21 


185.26 


175.80 


154.83 


146.47 


Curvilinear 


46 


181.21 


177.08 


168.04 


148.01 


140.02 


Seams, 


48 


177.77 


169.55 


160.94 


141.77 


134.12 


Single 


50 


170.55 


162.71 


154.41 


136.03 


128.69 


Riveted. 


52 


163.90 


156.40 


148.01 


130.73 


123.68 




54 


157.74 


150.49 


142.83 


125.84 


119.05 




56 


. 152.03 


145.05 


137.61 


121.29 


114.76 




58 


146.72 


139.99 


132.86 


117.01 


110.76 




60 


141.77 


135.26 


128.38 


113.13 


107.03 




62 


137.14 


130.85 


124.20 


109.44 


103.55 




64 


132.80 


126.74 


120.27 


105.99 


100.29 




66 


128.73 


122.83 


116.53 


102.75 


97.22 




68 


124.90 


119.18 


113.13 


99.70 


94.34 




70 


121.29 


115.74 


109.86 


96.85 


91.62 




72 


117.89 


112.49 


106.78 


94.11 


89.05 




74 


114.67 


109.42 


103.87 


91.55 


86.63 




76 


111.62 


106.51 


101.11 


89.12. 


84.33 




78 


108.73 


103.76 


98.49 


86.72 


82.15 




80 


105.99 


101.14 


96.01 


84.63 


80.08 



HAND-BOOK OF LAND AND MARINE ENGINES. 



897 



T A B L E — ( Concluded) 

OF SAFE INTERNAL PRESSURES FOR STEEL BOILERS. 



Birmingham 
Wire Gauge. 


3 


4 


5 


6 


7 


8 


Thickness 


.259 


.238 


.220 


.203 


.180 


.165 


of Steel. 


i Full. 


J Scant. 


A 


A Full. 


■j^Scant 


A Full. 




Dia. 


lbs. per 


lbs. per 


lbs. per 
sq. in. 


lbs. per 


lbs. per 


lbs. per 
sq. In. 




In. 


sq. in. 


sq. m. 


sq. m. 


sq. in. 


External 


24 


247.06 


226.62 


209.16 


192.72 


175.63 


156.14 


Diameter. 


26 


227.67 


208.87 


192.80 


177.66 


157.25 


143.98 




28 


211.10 


193.69 


178.80 


164.78 


145.87 


133.57 




30 


196.78 


180.57 


166.71 


153.65 


136.03 


124.57 




32 


184.28 


169.75 


156.14 


143.92 


127.43 


116.70 


Long. 


34 


173.27 


159.06 


146.84 


135.35 


119.85 


109.77 


Seams, 


36 


163.50 


150.07 


138.58 


127.75 


113.13 


103.61 


Single 


38 


154.73 


142.07 


131.20 


120.95 


107.12 


98.11 


Eiveted. 


40 


146.94 


134.88 


124.57 


114.84 


101.71 


93.16 


Curvil. 


42 


139.85 


128.38 


118.57 


109.32 


96.82 


88.69 


Seams, 


44 


133.42 


122.48 


113.13 


104.30 


92.39 


84.64 


Single 


46 


127.55 


117.10 


108.16 


99.73 


88.34 


80.92 


Eiveted. 


48 


122.18 


112.17 


103.61 


95.54 


84.63 


' 77.53 




50 


117.24 


107.64 


99.43 


91.68 


81.22 


74.41 




52 


112.69 


103.43 


95.53 


88.13 


78.07 


71.53 




54 


108.47 


99.60 


92.00 


84.84 


75.16 


68.86 




56 


104.56 


96.01 


88.69 


81.79 


72.46 


66.39 




58 


100.92 


92.67 


85.61 


78.95 


69.95 


64.08 




60 


97.53 


89.66 


82.74 


76.26 


67.60 


61.60 




62 


94.36 


86.65 


80.11 


73.17 


65.44 


59.93 




64 


91.38 


83.98 


77.53 


71.52 


63.35 


58.04 




66 


88.59 


81.36 


75.16 


69.32 


61.42 


56.28 




68 


85.97 


78.95 


72.94 


67.23 


59.60 


54.61 




70 


83.49 


76.68 


70.84 


65.34 


57.89 


53.05 




72 


81.16 


74.53 


68.86 


63.51 


56.28 


51.56 




74 


78.95 


72.50 


66.72 


61.78 


54.75 


50.16 




76 


76.86 


70.58 


65.21 


60.15 


53.30 


48.84 




78 


74.87 


68.76 


63.52 


58.60 


51.93 


47.58 




80 


72.99 


66.96 


61.94 


57.12 


50.62 


46.39 



34 



398 



HAND-BOOK OF LAND AND MARINE ENGINES. 




HAND-BOOK OF LAND AND MARINE ENGINES. 399 

MARINE BOILERS. 

There is now, as there always has been, a great 
diversity of opinion among engineers in regard to the 
true principles upon which to design a marine boiler 
which shall produce the greatest effect with the least 
stowage, first cost and subsequent labor, and fuel. But 
experience has shown that the best that can be done is to 
determine which of these considerations shall have the 
least weight, and to 'be governed accordingly, looking, as 
a guide, to practice rather than any assumed theoretical 
principles. 

For land purposes, there is hardly any limit to the size 
or weight of a boiler except first cost ; it is easy, therefore, 
to design and construct one with sufficient heating ^rface, 
water space, and steam room. But in designing a marine 
boiler the case is quite different, as the designer is restricted 
both in room and weight ; for if the vessel be occupied or 
loaded down with boilers, it detracts from the room and 
capacity that should be devoted to other purposes. 

Marine boilers are of necessity either flue or tubular, 
since the flame must be within the shell of the boiler ; but in 
this arrangement they are almost as various as the makers. 
The large flue is preferable because less liable to choke 
with soot, ashes, cinders, or salt which may come from 
leakage. But in situations which restrict length, height, 
and width of boiler, the only method of producing in a 
flue boiler such extent of fire surface as will extract all 
the heat capable of being used to advantage in generating 
steam, is to reduce the size and multiply the number of 
flues. 

The most ordinary forms of marine boilers are the hori- 
zontal and vertical ; and, so far as efficiency is concerned, 
there does not appear to be any great difference between 



400 HAND-BOOK OF LAND AND MARINE ENGINES. 

them where equal surfaces are presented to the action of 
the fire ; but there are many things, particularly in sea- 
going steamers, to be considered, and for them that boiler 
is the best which gives equal effect, occupies the least 
space, and affords the best facilities for cleaning and 
repairs. 

A certain proportion between the area of the grate and 
the total heating surface has been found productive of the 
best results, with a given description of fuel; but any 
alteration in the quality of the fuel used will be found to 
a'ffect this result materially. Consequently, no general 
rule can be laid down for the design of marine boilers 
that will answer for all kinds of fuel, nor is it at all likely 
that any one form will ever fulfil all the varied conditions 
under which such boilers may be placed. 

A considepation of great importance in the construc- 
tion of marine boilers is their capacity to contain water 
and steam. This, of course, depends upon the size of the 
boiler and the proportion of space occupied by flues or 
tubes, as, if the space within it be nearly filled with flues, 
there can be but little room left for water. 

In fixing on the proper capacity of the water-space of 
a marine boiler, there are not such peculiar difliculties as 
in the case of the steam-chamber, and any one at a first 
view of the matter would say, as many do without suflS- 
cient consideration, that there cannot be too little water, 
provided the boiler is filled to the proper height ; for it is 
quite obvious the smaller the quantity of water the less 
will be the expenditure of the fuel during the first getting 
up of the steam after each stoppage of the engine. It is, 
however, not the "getting up " the steam, but the keeping 
it up, that ought to be -considered of most consequence. 
It is a prevailing opinion that, after the steam is once got 
up, there is no material difference between keeping a large 



HAND-BOOK OF LAND AND MARINE ENGINES. 401 

quantity of water boiling and a small quantity, provided 
the escape of heat is prevented by sufficiently clothing the 
boiler with non-conducting substances ; but on this subject 
engineers differ. Why practical men should differ in 
opinion on so plain a matter is unaccountable. 

The quantity of water carried must exceed that of the 
evaporation in a given time, in order that the supply of 
feed-water may not greatly reduce the temperature of the 
water in the boiler and check the formation of steam. 
There must in all cases be a sufficient height of water in 
the boiler to prevent the flues or crown-sheet from becom- 
ing bare in case the supply of feed-water be neglected, or 
the vessel pitches in a rough sea. 

Steam room is understood to be the space in the shell 
of the boiler above the level of the water, and in marine 
boilers should be from ten to twelve times the capacity of 
the cylinder of the engine. This proportion has of necessity 
a very narrow limit of variation, as, if the steam room be 
less than the above proportions, at every stroke of the 
engine the pressure of steam on the surface of the water is 
liable to be reduced to such an extent as to produce violent 
ebullition or foaming. 

When boilers are sq constructed that steam cannot 
be taken off above the level of the water without the 
danger of working water into the steam-cylinder, it be- 
comes necessary to resort to the expedient of attaching a 
steam-dome to the boiler. This steam-dome is constructed 
either inside or around the smoke-pipe, which, though not 
adding much to the cubic capacity of the steam room, has 
the effect of superheating the steam, or imparting to it an 
extra heat, which greatly increases its expansive force and 
renders it less liable to condense in the passages between 
the boiler and the cylinder. 

34^ 2A 



402 



HAND-BOOK OF LAND AND MARINE ENGINES. 



PKOPOETIONS OF HEATING SUKFACE TO CYLINDER 
AND GRATE SURFACE OF NOTED OCEAN, RIVER, 
AND FERRY-BOAT STEAMERS. 









■fe^ '33 tM 


-M O <D 








a a o 


o c;-*a 








^03 


.3^ c3 c8 








<*H t<:5 +3 


*<-"« J~, 








i^i 




NAME OF STEAMER. 






ll« . 








OJ-S S <D 










limb 
hea 
1 c 

lind 


X2 eS C'S 
c o 00 5 








^-^B^ 


^"oS^ 


Powhatan, U. S. N 


14.8 


22.3 


Susquehanna, " " 


a 




16.25 


25. 


Mississippi, " " 


iC 




12.6 


18.6 


San Jacinto, " " 


u 




17.75 


27. 


Saranac, 


a 




14.5 


27.25 


Princeton, " " 


u 




28.8 


22. 


Michigan, 


a 




15. 


19.75 


Vixen, 


a 




18. 


16. 


Massachusetts, " " 


u 




77.4 


33.6 


Georgia, 


Merchant Steamer 


13. 


22.25 


Washington, 


u 


i( 


12. 


23.5 


United States, 


u 


u 


8.2 


21.9 


Northerner, 


ti 


it 


12.75 


24.9 


Falcon, 


i( 


n 


12.75 


20.8 


Philadelphia, 


u 


(I 


15. 


21. 


Republic, 


a 


u 


20. 


31. 


Ohio, 


u 


iC 


13. 


22.25 


Hermann, 


ti 


11 


14.8 


30.6 


Cherokee, 


n 


u 


12.17 


23.7 


Union 


u 


u 


118. 


66.4 


Constitution, 


iC 


cc 


93. 


34.5 


Golden Gate, 


u 


it 


17. 


32.8 


Monumental City, 


C( 


u 


51. 


31.5 


El Dorado, 


u 


i{ 


14. 


26.8 


City of Pittsburg, 


u 


l( 


30.9 


35.5 


Pioneer, 


u 


u 


28. 


33.5 


Albatross, 


u 


u 


57.25 


32.75 


Osprey, 


iC 


it 


27.5 


34. 


Humboldt, 


tl 


u 


12.8 


18.6 


Franklin, 


iC 


u 


11.3 


28.4 


Arctic, 


(( 


u 


21.5 


33.25 


Baltic, 


u 


u 


21.5 


33.25 


Pacific, 


(( 


il 


21.5 


33.25 


Atlantic, 


t( 


(( 


21.5 


33.25 



HAND-BOOK OF LAND AND MARINE ENGINES. 



403 



PKOPOETIONS OF HEATING SURFACE TO CYLINDER 
AND GRATE SURFACE OF NOTED OCEAN, RIVER, 
AND FERRY-BOAT STEAMERS. 





'^^ o 


' sq. feet 
surface 
of guate 


NAME OP STEAMER. 


Number oi 
of heating 
to 1 cubic 
cylinder. 


Number of 
of heating 
to 1 sq. ft. 
surface. 


Mav Flower. Merchant Steamer 


15.4 


31.71 


Empire State, " " 
America, " " 


14. 
33.75 


2415 
32.25 


Knoxville, " " 


15.33 


63.1 


North America River Steamer «.... 


13.6 
14.15 


22.3 
24.9 


South America, " " 


Oregon, " " 
Alida, 


12. 


31.3 


13.6 


27.9 


Niagara, " " 
Joseph Belknap, " " 
Mountaineer, " " 
New World, 


12.5 
21. 
12. 
11.3 


27. 
27.5 
32. 
25.17 


/ Traveller, 
Isaac Newton " " 


12.5 
10.6 


21.3 

28.2 


Roger Williams, " 


12. 


19.2 


Thomas Powell, " 


16.25 


25.5 


Armenia, " " 

America, 

Bay State, " " 


16. 

21.7 

12. 


24.5 

26. 

29.3 


Empire State, " " 
Baltimore, " " ■ 


11. 
22.10 


* 25. 
42.37 


J. M. White, Western river Steamer 


30. 


26. 


Rescue, Steam-tug 


63.3 


28. 


Anglo-Saxon, " 


10.1 


23. 


Merchant, Ferry-boat 


25.5 

16. 

15.5 


38. 
20. 
19.6 


Seneca, " 
Onalaska " 


John Fitch, " 

Average 


17.25 


22.3 


29.83 


28.08 



404 HAND-BOOK OF LAN^D AND MARINE ENGINES. 




SETTING MARINE BOILERS. 

In steams hips 7 it is advisable to place the boilers at or 
as near the centre of the- ship as possible, and at equal 
distances from the keelsons on each side, in order that 
there may be no difficulty in keeping the ship in trim, or 
changing her running line when necessary. 



HAND-BOOK OF LAND AND MARINE ENGINES. 405 

The boiler foundations ought to be laid so as to make 
the lower face of the boilers and the line of the tubes or 
flues parallel with the load line fore and aft. They 
should then be firmly secured with braces bolted to the 
hull, in order to prevent the possibility of their being dis- 
placed by any strain or motion to which the ship may be 
subjected. 

BEDDINa MARINE BOILERS, 

The manner of bedding marine boilers is a point of 
much importance, and will materially affect the durability 
of the bottom plates. The general practice in this country 
is to form a close platform of 2} or 3 inch yellow pine 
plank over the keelsons, upon which the boiler is imbedded 
with a cement composed of drying oil and whiting, laid 
about IJ inches over the plank; this cement sets quite 
hard, and prevents any dampness or bilge water from 
rusting or corroding the boiler. The cement is also intended 
to stop any leaks that may break out in the bottom or 
water-legs. 

Unfortunately, however, the benefits to be derived from 
such a bedding are frequently lost in consequence of the 
unequal degrees of expansion between the cement and the 
boiler. The best practice is, perhaps, that of resting the 
boiler on saddles of cast-iron fixed on the boiler bearers, 
which leaves the bottom exposed for examination, paint- 
ing, and small repairs, if necessary ; the bottom of the 
vessel under the boilers being at the same time kept clean 
and dry by the bilge-pumps. 

CLOTHING OF MARINE BOILERS. 

Although it must be allowed that in all cases the clothing 
of marine boilers with non-conducting substances, such as 
hair-felt, wood, etc., is highly advantageous for the pro- 



406 HAKD-BOOK OF LAND AKD MARINE ENGINES, 

duction of steam, yet this practice is alleged in some 
instances to have induced a rapid wear in the plates of 
the boiler. This unlooked-for result is most apparent in 
boilers which are frequently used and disused alternately, 
the corrosion taking place on the interior surface. 

The conjecture as to its cause is, that owing to the 
alternate whetting and drying of the plates of the clothed 
boiler, the rust may be more apt to scale off, and thus 
constantly present a clean surface for corrosion, this action 
recurring each time that the water is blown out of the 
boiler ; but when, on the other hand, the boiler is naked, 
the internal surface never thoroughly dries, owing to the 
evaporation being checked by the low temperature, and 
the saturation of the confined air. 

The clothing of marine boilers which make long 
voyages is never attended with these injurious results, 
nor are they ever experienced in land boilers. 

CARE OP MARINE BOILERS. 

iVIarine boilers require much attention, both at sea and 
in port, especially if they be complex tubular constructions. 
The great points at sea are, the firing, the feeding, and the 
blowing off; the great points in port, the cleaning and 
repairing. If the boiler be blown off by means of blow- 
off cocks, the operation should be performed twice in the 
watch, or once in every two hours. The feed should be 
so set that the water will rise in the course of two hours 
from a little below the middle to near the top of the glass 
gauge tube ; the rule being to blow off so frequently, or so 
much, as to prevent any accumulation of scale within the 
boiler. 

In boilers furnished with brine pumps, reliance must 
not be placed upon the pumps always acting well, and 
once every watch some water should be drawn off from 



HAND-BOOK OF LAND AND MARINE ENGINES. 



407 



the boiler, to be tested by a salt gauge, to see whether it is 
too salt or not. When the water has been evaporated to 
such an extent as to reduce its volume some three- or four- 
fold, the saltness becomes so excessive that solid salt is 
liable to form upon the exposed surfaces. 




Vertical Tubular Marino Boileri 



The saltness of opdinary sea-water varies somewhat in 
different places, but, as a general rule, there is about one 
pound of salt in every thirty-three of sea-water. When, 



408 HAND-BOOK OF LAND AND MARINE ENGINES. 

by boiling, the proportion of salt is increased to about 3^, 
the formation of a scale consisting mainly of salt is likely 
to commence. It is important, therefore, to blow out a 
portion and to supply its place by new, so often as to keep 
the water fresher than 3^ ; but, on the other hand, every 
exchange of hot water for cold diminishes the supply of 
steam and increases the consumption of fuel. 

To ascertain the sal tn ess of water as accurately as pos- 
sible, hydrometers and salinometers are generally em- 
ployed. But in the absence of these instruments, the 
engineer may make one for himself in the following man- 
ner : Take a glass phial or cologne bottle, pour into it so 
much shot that it will nearly sink in sea-water, and then 
cork it tightly. Take any convenient weight of boiling 
water, say 33 pounds ; dissolve therein 1 pound of salt, 
and then put the phial into it, turned upside down, so that 
the shot will rest against the cork ; make a mark with a 
file at the point at which the water stands on the phial ; 
this represents the saltness of sea- water. Then add another 
pound of salt to the water, marking the point, as before, 
on the phial at which the water stands, and repeat the 
operation until 12 pounds of salt have been added, at 
which point the water will have received as much salt as 
it can dissolve ; transfer the marks upon the bottle to a 
paper scale, which paste on the inside of the bottle in ex- 
actly the same position as the original marks. 

The engineer will then have a salt gauge which will 
tell the saltness of brine from the point of sea- water up to 
the point of situation. Keckoning sea-water at 1, the 
water in the boiler should not exceed the saltness repre- 
sented by 4, at which point the water contains -3^3 of 
salt. It is not probabk that this rude contrivance will 
often be made, but the description may be of service in 



HAND-BOOK OF LAND AND MARINE ENGINES. 409 

explaining the nature of the more elaborate and accurate 
instruments sold for the purpose. 

If a vessel is to remain in port any length of time 
after the boilers become cool, the hand-hole plates over 
the furnaces should be removed in order to ascertain if 
there are any heavy deposits on the crown-sheet ; the bot- 
tom hand-hole plates should also be taken out, so as to 
allow the water to drain out and permit a current of air 
to pass through, as mere dampness is more injurious than 
actual use, in consequence of the rapid oxidation it in- 
duces. In cases where circumstances forbid the removal 
of the bottom hand hole plates and draining of the boilers, 
it is preferable that they should remain full rather than 
have only a small quantity of water in the bottom. 

REPAIRING STEAM-BOILERS. 

Repairing steam-boilers is generally attended with 
more or less difficulty, arising from the peculiar type of 
boiler and the cramped and inconvenient location in which 
the repairs generally have to be made, and also, in many 
cases, the want of proper facilities at the time and location. 

The two most ordinary methods of patching boilers 
when they crack or burn out, and, in fact, the only two 
that can be successfully employed, are the hard and soft 
patching. The former is the most permanent and reliable; 
but it is only practicable where nearly all the facilities re- 
quired by boiler-makersi are at hand. The soft patching 
process is generally resorted to in repairing the boilers of 
steam-vessels when at sea, or the boilers of locomotives in 
sections of country where it is impossible to employ the 
hard patch. 

To apply the hard patch, it is necessary to lay off its 
dimensions on the plate to be patched, allowing from 1 to 
1| inches of sound material outside of the crack or flaw. 
35 



410 HAND-BOOK OF LAND AND MARINE ENGINES. 

The patch is next drilled for the rivet-holes, and its edges 
chipped ; it is then placed over the defective part, and the 
holes marked through it by means of a small tube dipped 
in white paint. The holes are next drilled in the sheet with 
a ratchet-drill and brace ; the defective material in the 
sheet is then cut out, in order to allow the w^ter to come 
in contact with the patch, which is then riveted on and 
calked ; but in case it should be found impossible, for want 
of space, to rivet it, it is put on with tap-bolts. 

The soft patch is prepared in the same way, but ap- 
plied differently, it being first covered with a heavy coat 
of cement, and then attached to the defective place by 
means of bolts, nuts, and washers ; a grummet of hemp 
being placed under the head of each bolt and washer to 
make it steam- and water-tight. 

The hard patch is more suitable for furnaces and parts 
of the boiler exposed to the action of the fire, while the 
soft answers very well for the steam room and water 
space. 

TUBES. 

The use of tubes is to conduct heat to the surrounding 
water at the least possible cost, the items of cost being, 
1st, waste heat ; 2d, maintenance of tubes. Granted that 
the best conducting tube is the least durable, and that the 
poorest conducting tube is the most durable, the question 
is. By avoiding which species of expense shall the highest 
economy be attained ? 

The resistance of tubes is manifestly due entirely to 
their hardness; the materials ranging in the following 
order : steel, iron, brass, copper. 

Iron has, heretofore, more especially where anthracite 
coal has been used as fuel, nearly superseded all other 
materials for tubing on account of its hardness and good 
flanging qualities ; but at the present time steel seems to 



HAISTD-BOOK OF LAND AND MAEINE ENGINES. 411 

afford better results than any other material, as the tubes 
can be made lighter, and possess steaming qualities equal, 
if not superior, to either copper or brass ; while the nature 
of the material affords the requisite degree of surface 
resistance to the chemical action of the water in the 
boiler. 

The failure of tubes might in the majority of cases be 
attributed to a contracted water space, bad circulation 
between them, and the deposit of scale adhering to the 
outer surface caused by impurities in the water. 

Diameter and Arrangement of Tubes. — Tubes two 
inches in diameter, placed in vertical rows J of an inch 
apart, give most satisfactory results, as such an arrange- 
ment admits of an easy circulation of the water and free 
escape of steam from the heating surface to the steam- 
dome, besides giving ready access to the mud in its pass- 
age from the water to the bottom of the boiler. 

Crowding tubes in tubular boilers is often carried to 
an extreme with the view of getting more surface, but 
without regarding the other conditions of steam-raising. 
Heating surface in the abstract is one thing, its efficiency 
is another, as the under portions of the tubes and internal 
flues are almost worthless for steam-raising, not only on 
account of the difficulty the steam has in escaping from 
the surface on one side, but also in consequence of the 
deposit of soot, ashes, and flue dirt which is the rule on 
the other. 

The incrustation also accumulates much more rapidly, 
and to a greater thickness, on the under side than on the 
crown of tubes, especially of large diameter, principally 
on account of the comparatively quiescent state of the 
water in contact with the former. 

Assuming the gases entering a tube to be all of the same 
temperature, the particles striking against the upper sur- 



412 HAND-BOOK OF LAND AND MARINE ENGINES. 

face must give up part of their heat, and, in cooling, descend 
by virtue of their increased gravity, despite the onward 
and upward force due to the momentum of the mass which 
opposes their descent. The hot particles immediately be- 
hind and beneath these will come in contact with the 
upper surface a little further on, and so a species of con- 
vection is kept up as the gases sweep along. 

In horizontal tubes various means have been devised 
for extracting more of the heat out of the gases than 
they will yield by radiation or conduction through their 
mass, by breaking the current at intervals, and so bringing 
fresh portions of the gases in contact with the plates, by 
giving them a zigzag motion ; this, however, has the effect 
of impairing the draught and, in most cases, of causing a 
reduction in the evaporative capacity of the boiler. 

In passing up through vertical tubes gases act at a dis- 
advantage for imparting their heat to the plates. The 
particles cooled by contact with the sides on entering 
have no tendency to make way for those in the middle of 
the current that still retain their heat, which can there- 
fore only be indifferently imparted by radiation or con- 
duction. 

The evaporative eflRciency of tubes, as before stated, 
depends on the nature, condition, and thickness of the 
material forming the tubes. In tubes manufactured from 
homogeneous metal, the resistance to internal conduction 
is proportional directly to the distance the heat has to 
traverse or to the thickness of the tube, and inversely to 
the difference of temperatures between the two surfaces. 



HAND-BOOK OF LAND AND MAKINE ENGINES. 413 



TABLE 

OF SUPERFICIAL AREAS OF EXTERNAL SURFACES OF TUBES OF 
VARIOUS LENGTHS AND DIAMETERS IN SQUARE FEET. 

. These tables are designed to facilitate the calculation 
of the heating surface of the tubes in tubular boilers, and 
are adapted for tubes of various lengths, from 8 to 13 feet, 
advancing by inches, and of various diameters, from If to 
2^ inches, advancing by | of an inch. 

EXPLANATION. 

The large figures at the end of the horizontal lines give 
the length of the tubes in feet, and the small intermediate 
figures on the same line give the additional inches. The 
vertical column on the left gives the diameter of the tubes 
in inches. The numbers in the tables represent the 
superficial area of one tube in square feet, and decimal 
parts thereof, for the difierent lengths and diameters of 
tubes required. 

EXAMPLE. 

Kequired the heating surface of 163 tubes, 1| inches 
diameter and 11 feet 10 inches Ipng. Thus, having found 
the length (11 feet 10 inches) in the above named hori- 
zontal line of figures, trace downwards to the line 
opposite the diameter (1|) in the vertical column on 
the left, where will be found the number 5*421, being the 
area of the tube, and which, being multiplied by the 
number of tubes (163), gives the total area of 883,623 
square feet, thus reducing the whole process to a simple 
matter of multiplication. 
35* 



HAND-BOOK OF LAND AND MARINE ENGINES. 



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HAND-BOOK OF LAND AND MARINE ENGINES. 



415 





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HAND-BOOK OF LAND AND MARINE ENGINES. 



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HAND-BOOK OF LAND AND MARINE ENGINES. 417 

BOILER FLUES. 

The well established law that the strength of cylinders 

is inversely as their diameters, and the hitherto undis- 
puted axiom among practical engineers, that cylindrical 
tubes or boiler flues when subjected to uniform external 
pressure were equally strong in every part regardless of 
length, led to erroneous opinions regarding the strength 
of boiler flues. 

Fop flues to collapse, under the ordinary working press- 
ure of steam in what was supposed to be properly propor- 
tioned and well-made boilers, was formerly not an unusual 
occurrence ; and although many theories were advanced 
on the subject, it was not until the celebrated English 
engineer, William Fairbairn, LL.D., F. E. S., made an 
extensive set of experiments on the strengths of tubes of 
various forms, sizes, and lengths, that the hidden weakness 
was revealed. 

These experiments were made by hydrostatic pressure, 
applied both externally and internally, to test the strength 
under ordinary conditions of practice, and they proved 
conclusively that the strength of flues exposed to external 
pressure, as ordinarily used, is inversely as the length; 
that is, a flue 20 feet long will collapse with just half the 
pressure of a flue 10 feet long, everything else being equal ; 
in other words, a flue 20 feet long, which would bear a 
pressure of 90 pounds per square inch, if shortened to 10 
feet, or, what is the same thing in effect, if it be hooped 
in the middle of its length by angle or T iron, it will then 
bear a pressure of 180 pounds per square inch. 

Although it had long been established that a circle is 
the strongest possible form that can be made, and that no 
deviation from it can be made without reduction of strength; 
yet it was not previously known that a 9-inch diameter 

2£ 



L 



418 HAND-BOOK OF LAND AND MARINE . ENGINES. 

of tube was reduced in strength more than one-third by 
deviating from a circle only sufficient to make a lap-joint, 
the ratio being as 7 to 10 — so proved by tests. 

When pressure is exerted within a tube or cylinder 
with spherical ends, the tube can only give way by the 
metal being torn asunder ; and the tendency of the strain 
is to cause the tube to assume the true cylindrical figure, 
or spherical form — the form of greatest resistance. With 
pressure exerted on the outside of a tube, the tendency of 
that pressure is to crush in the tube — to flatten it. 

It is a well-known fact that iron of any strength, when 
formed into a tube, will bear a much greater strain to tear 
it asunder, if that pressure be applied internally, than it 
will bear without crushing in, when applied externally, 
A bar of iron, when used as a tie-rod, will resist a very 
large amount of tearing force ; but that same bar, placed 
as a prop only, under the weight exerted in the former 
case, would be doubled up and crushed out of form. 

The inner tubes of boilers are nothing more nor less 
than a series of props, as they have to sustain the immense 
weight of the pressure exerted externally on their diameter. 
The constant and never-ceasing tendency is for those props 
to give way — for the cylindrical tube to depart from the 
form of greatest resistance, to become flattened or bulged, 
and ultimately crushed in. 

The foregoing conclusions show the imperative necessity 
of adhering to the true circle for boiler flues, more 
especially where high-pressure steam is used. 

Rule for finding the Safe External Pressure on Boiler 
Flues, — Multiply the square of the thickness of the iron 
by the constant whole number 806,300 ; divide this pro- 
duct by the diameter of the flue in inches ; divide the quo- 
tient by the length of the flue in feet ; divide this quotient 
by 3. The result will be the safe working pressure. 



HAND-BOOK OF LAND AND MABINE ENGINES. 419 

EXAMPLE. 
Diameter, 13 inches. Length, 10 feet. 

Thickness, | of an inch, 13 diameter. 

10 length. 

1X1 = A- 130 

3 

390 

7256700 ^^^ 7256700 
^% X 806,300 = — gj- ^ 390 - -^^^ = 29073 safe , 

external pressure. ^ ^ ^ 

TABLE 

OF SQUARES OF THICKNESSES OF IRON, AND CONSTANT NUMBERS TO 

BE USED IN FINDING THE SAFE EXTERNAL PRESSURE FOR BOILER 

FLUES. 

Birmingham 
Gaugo. 

I -375 X -375 X 806,800 = 113,385-937500 

00 -358 X -358 X 806,300= 103,338-633200 

-340 X -340 X 806,300 = 93,208-280000 

1 -800 X -300 X 806,300 = 72,567-000000 

2 -284 X -284 X 806,800 = 65.032-932800 

3 -259 X -259X806,300= 54,087-410300 

4 -238 X -288 X 806,800 = 45,672 057200 

5 -220 X -220 X 806,300 = 39,024-920000 

6 -203 X -203 X 806,800 = 33,226-816700 

7 -1 80 X -180X806,800= 26,124-120000 

8. -165 X -165 X 806,300 = 21,951-517500 

Explanation. — The column on the left-hand side of the 
page, |, 00, 0, 1, etc., represents the number of the boiler 
iron according to the Birmingham wire gauge ; the second 
and third columns, '375, '358, etc., represent the decimal 
parts of an inch, the inch being taken as 10,000, which 
columns being multiplied together give the square of the 
thickness of the iron; the fourth column represents the 
constant number 806, 300, by which we multiply the sev- 
eral squares of the thicknesses; the fifth column represents 
the several products. 



420 



HAITD-BOOK OF LAND AND MARINE ENGINES. 



TABLE 

OF SAFE WORKING EXTERNAL PRESSURES ON FLUES 10 FEET LONG. 



BIRMINGHAM 
GAUGE. 


1 


00 





1 


2 


Thickness 
of Iron. 


.375 


.358 


.340 


.300 


.284 


Diam. in In. 












6 


629.92 


574.10 


517.82 


403.15 


361.29 


7 


539.93 


492.08 


443.85 


345.56 


313.96 


8 


472.44 


430.58 


388.37 


302.36 


270.97 


9 


419.95 


382.74 


345.22 


273.95 


240.86 


10 


377.95 


344.46 


310.69 


241.89 


216.78 


11 


343.59 


313.15 


282.45 


219.56 


199.80 


12 


314.12 


287.05 


258.91 


201.58 


180.65 


13 


290.73 


264.97 


238.99 


186.07 


166.75 


14 


269.97 


246.04 


221.92 


172.78 


154.84 


15 


251.97 


229.64 


207.13 


161.26 


144.51 


16 


236.22 


215.28 


194.18 


151.18 


135.49 


17 


222.33 


202.62 


182.76 


142.28 


125.06 


18 


209.97 


191.18 


172.61 


134.38 


120.43 


19 


198.92 


181.12 


163.52 


127.72 


114.09 


20 


188.98 


172.23 


155.35 


120.95 


108.39 


21 


179.98 


164.02 


147.95 


115.19 


103.23 


22 


170.28 


156.57 


141.23 


109.95 


98.53 


23 


164.33 


149.76 


135.08 


105.17 


94.25 


24 


157.48 


143.53 


129.46 


100.79 


90.32 


25 


151.18 


137.78 


124.28 


96.76 


86.71 


26 


145.37 


132.79 


119.50 


93.03 


83.37 


27 


139.98 


127.58 


115.07 


89.58 


80.28 


28 


134.98 


123.02 


110.96 


86.39 


77.42 


29 


130.33 


118.79 


107.14 


83.41 


74.75 


30 


125.98 


114.82 


103.56 


80.63 


72.25 


32 


118.11 


107.65 


97.09 


75.55 


67.74 


34 


111.16 


101.31 


91.38 


71.14 


63.75 


36 


104.99 


95.68 


86.30 


67.19 


60.21 


38 


99.46 


90.65 


81.76 


63.65 


57.04 


40 


94.49 


86.11 


77.67 


60.47 


54.19 


42 


89.99 


82.00 


73.97 


57.59 


51.61 



HAND-BOOK OF LAND AND MAKINE ENGINES. 



421 



TABLE — (Continued) 

OF SAFE WORKING EXTERNAL PRESSURES ON FLUES 10 FEET LONG. 



BIRMINGHAM 
GAUGE. 


3 


4 


5 


6 


7 


8 


Thickness 
of Iron. 


.259 


.238 


.220 


.203 


.180 


.165 


Diam. in In. 














6 


300.49 


253.73 


216.81 


184.59 


145.14 


121.95 


7 


257.56 


217.49 


185.83 


158.22 


124.40 


104.53 


8 


225.36 


190.30 


162.60 


138.45 


108.85 


91.46 


9 


200.32 


169.16 


140.83 


123.06 


96.76 


81.30 


10 


180.29 


152.24 


130.08 


110.76 


87.08 


73.17 


11 


163.90 


138.40 


118.26 


100.69 


79.16 


66.51 


12 


150.24 


126.87 


108.40 


92.30 


72.56 


60.97 


13 


138.69 


117.11 


100.06 


85.20 


66.98 


56.28 


14 


128.78 


108.74 


92.92 


79.11 


62.20 


52.26 


15 


120.19 


101.49 


86.72 


73.83 


58.05 


48.78 


16 


112.68 


95.15 


81.30 


69.22 


54.42 


46.10 


17 


106.05 


89.55 


76.51 


65.15 


51.22 


43.04 


18 


100.16 


84.58 


72.26 


61.53 


48.37 


40.65 


19 


94.89 


80.13 


68.46 


58.29 


45.83 


38.51 


20 


90.15 


76.12 


65.04 


55.37 


43.54 


36.58 


21 


85.85 


72.49 


61.92 


52.74 


41.46 


34.84 


22 


81.95 


69.20 


59.12 


50.34 


39.58 


33.25 


23 


78.38 


66.19 


56.55 


48.15 


37.86 


31.81 


24 


75.12 


63.43 


54.20 


46.14 


36.28 


30.48 


25 


72.11 


60.89 


52.11 


44.30 


34.83 


29.26 


26 


69.34 


58.55 


50.03 


42.59 


33.49 


28.91 


27 


66.77 


56.38 


48.17 


41.02 


32.25 


27.10 


28 


64.38 


54.37 


46.45 


39.55 


31.10 


26.13 


29 


62.16 


52.49 


44.85 


38.19 


30.02 


25.23 


30 


60.09 


50.74 


43.36 


36.91 


29.02 


24.39 


32 


56.34 


47.57 


40.65 


34.61 


27.21 


22.86 


34 


53.02 


44.77 


38.25 


32.57 


25.61 


21.52 


36 


50.08 


42.38 


36.13 


30.76 


24.18 


20.32 


38 


47.44 


40.06 


34.23 


29.14 


22.91 


19.25 


40 


45.07 


38.06 


32.52 


27.68 


21.77 


18.29 


42 


42.13 


36.24 


30.97 


26.37 


20.73 


17.42 



36 



422 



HAND-BOOK OF LAND AND MARINE ENGINES, 



TA^IL'K — (Continued) 

OF SAFE WORKING EXTERNAL PRESSURES ON FLUES 20 FEET LONG. 



BIRMINGHAM 
GAUGE. 


1 


00 





1 


2 


Thickness 
of Iron. 


.375 


.358 


.340 


.300 


.284 


Diam. in In. 












6. 


314.96 


287.05 


258.91 


201.58 


180.65 


7 


269.97 


246.04 


221.93 


172.78 


156.98 


8 


236.22 


215.29 


194.18 


151.18 


135.49 


9 


209.97 


191.37 


172.61 


136.98 


120.43 


10 


188.98 


172.23 


155.35 


120.95 


108.39 


11 


171.80 


156.57 


141.26 


109.78 


99.90 


12 


157.06 


143.53 


129.46 


100.79 


90.32 


13 


145.37 


132.49 


119.50 


93.03 


83.38 


14 


134.98 


123.02 


110.96 


86.39 


77.42 


15 


125.98 


114.78 


103.56 


80.63 


72.26 


16 


118.11 


107.64 


97.09 


75.59 


67.74 


17 


111.16 


101.31 


91.38 


71.14 


62.53 


18 


104.99 


95.59 


86.31 


67.19 


60.22 


19 


99.46 


90.56 


81.76 


63.86 


57.05 


20 


94.49 


^6.12 


77.68 


60.47 


54.19 


y 21 


89.99 


82.01 


73.98 


57.59 


51.61 


22 


85.14 


78.29 


70.62 


54.98 


49.27 


23 


82.16 


74.88 


67.54 


52.58 


47.13 


24 


78.74 


71.76 


64.73 


50.39 


45.16 


25 


75.59 


68.89 


62.14 


48.38 


43.36 


26 


72.68 


66.54 


59.75 


46.52 


41.68 


27 


69.99 


63.79 


57.54 


44.59 


40.14 


28 


67.49 


61.51 


55.48 


43.20 


38.71 


29 


65.17 


59.39 


53.57 


41.70 


37.37 


30 


62.99 


57.42 


51.78 


40.31 


36.12 


32 


59.06 


53.82 


48.55 


37.77 


33.87 


34 


55.58 


50.66 


45.69 


35.57 


31.87 


36 


52.50 


47.84 


43.15 


33.59 


30.10 


38 


49.73 


45.38 


40.88 


31.82 


28.52 


40 


47.24 


43.05 


38.83 


30.23 


27.09 


42 


44.99 


41.00 


36.98 


28.79 


' 25.80 



HAIfD-BOOK OF LAND AND MARINE ENGINES. 



423 



T A B L 'E — (Concluded) 
OF SAFE WORKING EXTERNAL PRESSURES ON FLUES 20 FEET LONG. 



BIRMINGHAM 
GAUGE. 


3 


4 


5 


6 


7 


8 


Thickness 
of Iron. 


.259 


.238 


.220 


.203 


.180 


.165 


Diam. in In. 














6 


150.25 


126.87 


108.40 


92.30 


72.57 


60.98 


7 


128.78 


108.75 


92.92 


79.11 


62.20 


52.27 


8 


112.68 


95.15 


81.30 


69.22 


54.43 


45.73 


9 


100.16 


84.58 


70.42 


61.53 


48.38 


40.65 


10 


90.15 


76.12 


65.04 


55.38 


43.54 


36.58 


11 


81.95 


69.20 


59.13 


50.35 


39.58 


33.25 


12 


75.12 


63.44 


54.20 


46.15 


36.28 


30.48 


13 


69.35 


58.56 


50.03 


42.60 


33.49 


28.14 


14 


64.39 


54.37 


46.46 


39.55 


31.10 


26.13 


15 


60.10 


50.75 


43.36 


36.91 


29.02 


24.39 


16 


56.34 


47.58 


40.65 


34.61 


27.21 


23.05 


17 


53.03 


44.78 


38.25 


32.57 


25.61 


21.52 


19 


50.08 


42.29 


36.13 


30.76 


24.18 


20.32 


47.45 


40.07 


34.23 


29.14 


22.91 


19.25 


20 


45.08 


38.06 


32.52 


27.68 


21.71 


18.29 


21 


42.93 


36.24 


30.96 


26.37 


20.73 


17.42 


22 


40.98 


34.60 


29.56 


25.17 


19.79 


16.62 


23 


39.19 


33.09 


28.27 


24.07 


18.93 


15.90 


24 


37.56 


31.71 


27.10 


23.07 


18.14 


15.24 


25 


36.05 


30.44 


26.05 


22.15 


17.41 


14.63 


26 


34.67 


29.27 


25.01 


21.29 


16.74 


14.45 


27 


33.38 


28.19 


24.08 


20.51 


16.12 


13.55 


28 


32.19 


27.18 


23.22 


19.77 


15.55 


13.06 


29 


31.08 


26.24 


22.42 


19.09 


15.01 


12.61 


30 


30.04 


25.37 


21.68 


18.45 


14.51 


12.19 


32 


28.17 


23.78 


20.32 


17.30 


13.60 


11.43 


34 


26.51 


22.38 


19.12 


16.28 


12.80 


10.76 


36 


25.04 


21.19 


18.06 


15.38 


12.09 


10.16 


38 


23.72 


20.03 


17.11 


14.57 


11.45 


9.62 


40 


22.53 


19.03 


16.26 


13.84 


10.88 


9.14 


42 


21.06 


18.12 


15.48 


13.18 


10.36 


8.71 



424 HAND-BOOK OF LAND AND MARINE ENGINES. 

Rule for finding the Collapsing Pressure of Boiler Flues. 
— Multiply the square of the thickness of the iron, in 
thirty-seconds of an inch, by the constant number 262'4 ; 
divide this product by the length of the flue in feet ; di- 
vide this quotient by the diameter of the flue, in quarter 
feet, and the quotient will be the collapsing pressure in 
pounds per square inch. 

EXAMPLE. 

Diameter of flue, 24 inches. 
Length of " 10 feet. 
« Thickness of iron, f in. 

12 12 

Thickness, I = —. ^^ 

Diam. 24 in. = 8 quarter ft. I44 

262.4 
576 
288 
864 
288 



10) 37785-6 
8 )3778-56 

472-32 pounds. 

Explanation of the following Tables of Collapsing 
Pressures. — The outside vertical column on the left-hand 
side of the table gives the length of the flue in feet; the 
horizontal column at the top of the table gives the diam- 
eter of the flue in inches. All the other columns denote 
the collapsing pressures in pounds per square inch. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



425 





Length 
in Feet. 


Crt>*i.CnOiO<:nCOC?iOOH-'000>«DCOIs300 


o 


s 

1 

p 

CD 

p* 

8 

1 


H-i^a,-iH-iK-'»-iHii-^tofcObococo>;^anciO 


1—* 

to 




Ox 


^QOOOOOOi-'tOrf^C^^OCCOOC^CiCO 
-^ to ^1 W O ^ 05Q0005C;nOWOOOi<:0 


1— I 

00 


Oi-^l^OOOOOOOOtOCOOi^Oh^OOO 
OiOCrtOO^fcOOcDOCOOH-'OOOOO 


fcO 


OOi-*C7«OCnO^O^O^a)>-'OO^OtOcOCn 


to 






1^ )_i H-t I-- tC bO *>. 


CO 

o 


h-i (-» j-i 1— I bO CO 
4!>.>;kt^C;tO^CnO:i05-^100cDObOCr<cOCnQO 
tOC;<-'4t-*^^QOCOcOOi(yiCn;C>"^tOH-^4;fctO 


CO 
CO 


i_j (_a 1—1 i-J to CO 
CO*fc.>^f;».OxCnC;iOS^1^10DO'-'V^^C04i. 
COl-»rfi.0iO4».00rf^O0C^lO0iOOiC0C0 


CO 



36* 



426 



HAND-BOOK OF LAND AND MARINE ENGINES. 



CO CO 00 CO tS fcO bO to to '-' I-* t-i l-i H-i 

a>tf*'fcoocoo5*i.tooooc5rfi^tooQoajrf^ 



Length 
in Feet. 



l-» •-» bO 

fcOfcOtOfcOCOCOOOCOrf:^>^C;nas*qQCOi4i^»-» 
rfik.Cr^-^<yDI— '00CiC£)COQ04*.tOtO^lCOCnGO 
CO-aCO»-'tOOi»*^Q0^O5OiaiCO<yTiCO00^ 



l-»HJtOfcOtObOtOtOCOCO»^*».Oi05000ai 
OOOOi-*COCn^l<:Dt005K-»o:>4^0xtO<y3rf^ 
bOCOOiQOM^tOCOQOOO^OQOOdCdOCOO 



KJ»-iH^»-*KJtotototobococo>^aiOiCooo 

►^C;x05-<IQCO»— '00Ci<:DtO-^C0tOC?«-<|i— k 
C5rf^*».Ot-qtOC»QObOfcOQOOT^^05aitO 



H-»^UH-«i-«t-')-'r-i|-*bOtObOCOCOl^Cn^O 
tObOOO*i.OiaiGOCD>-'a^-<Ii— »05CO»*^bOCO 
^-^C0050^05QOtOOGOCO&Ot0^^i>'^Oi<X»CO 



)-iHJl-»H-*l-4|-»h-it-«h-»tOtOtOCCOOk^OCD 
Ol-i|-*tOCO>4^0i-vlOOOCOC55H-'^05tOOO 
rii«.O*aCnC0rfik0iO«<lQ0rfi.^t0rfi»Q0hP*.'^ 



>_ii_iH-ii-'.-»»-»(-*t-*bOCOtO004i.C;ri00 
COcDOOi-'tOCO>4:i.C:>QOOtO-4tOi-'rf^tO 
H-kCStO<;D*4050i;Drf^fcOir«k4i^COQOOC50 



>-i|-»f»jiH^H-*H^(-«tOtOtOC04i^^ 

OOOOCOCOOi-ttOCOht^OiQOO^^COOSOOtO 
»-*Oih-*-^rf^tOt-*OOCifcObOOOCOtOrfs^OiCD 



H-i >-» l-t H-t »-« h-* l-» to to CO 45* C5 

•>~1^aOOOO?DOOi--»C045*0500i— iCStOCOC^ 
(W-aLO^COl-'cOCOH-'O5>^fcO00tOG0-^O5 



H-»t»iH-it-'>-i|-ltOtOCOCn 
Oi-'^^^-^IQOsDcDOH-'COrfJ^^JCDOOOcDCO 
0iOrf!»<:DCntOc0QD<£>C0c0O<OC»Q0C»0:> 



f-»l-*l— i»-»(-^tOtOCOCrt 
C5Ci05-<l'<lOO<:DcC>OtOCCO^QOH-'^iO:»*>' 
0>45'OOtOOOrfi».l-'COCDH-»OOifcOaOOOrfi>.Ci 



I 



HAND-BOOK OF LAND AND MARINE ENGINES. 



427 



Oit^tOOOOOitf^UiOQOOSH^tOOOOO^M^ 



Length 
in Feet. 



»-*»-* h-A tC CO 
COCOCCh^>4;i.>^CrtCnOiOi-^COOlNiCnOt-' 
Oi-^COtOOtQDtsD-4COCOOOOa»C5— ICO**- 



H-i H-* to 
lNDbObCC0C0CC00»*i^><i».OtCnO5-<ICDi— 'OxOO 
O5'^lcDt-^0iOi«OtO^lbScO^J004i.00^^O5 


1— 1 

to 


bOfcObOfcOt>Otv50000CCh^>4i>^Oi05^:DfcN5QC 
OtOCitsSOfcOOxCOOOOfcCOOOSjis^OCO 


on 



K_i^H-'tofcObotoiocococo>;i.oi05-qooi 

•-qQOCOH-itOai^CniQOt-'OxcOOifcOCOQO*'.'^ 

c;1C;l050o^^^fcoo50lOcoooo^cDrf^ 


>-* 
00 


,»iHih-»l-»>-'tOtOlN5fcOCOCOCOrf^Ox05cDCO 
C7tCnC:OOcOOfcOrf^^lOCOGOa»t^-aOrf^ 

ooooooto^iC7icnooM<:noo>4i>'OcD 


bO 


H-i|_»H-iH-»h-*>-»>-'isDtotofcO«>oa>*i.c;^^^ 

COCO^UCnO500CDt— C005(:OCOCD^1COQOQD 

H-Aco--i^ooK-i05rf^oito<:y<icofcoo^o 


bO 



,_ii-AH-ih-it-»>-*i-*i-*fcOfcObOcoco»^c;iC50 

t-*bOC0^4ii.OiC5^1CDi--A<i*3 0iOCr«tOtOcDrfi. 
•<loai— iOOi--'Oii-'C;ia)lOOOOCncOcD 



^j|-iH-»t-il-*^>-i»--»t-«tOtOtsDCOCC>^05CD 
Oi-»i-*t000>^Ot^l00h-'C0^IH-i^-lC0 4^ 
Oi»-*00050iOi'^l»-*<^OCJOCnQOfcOO** 



«DOOi— ^tOCCrfa-Ox— ICDt-'O^OO^^tO-^IOi 
Cr<>-"^CitOt0 05 0afcOh->>;^CnOJ><J».'X>fcOQO 



. i-_i,_i|-iH_.(-iK-»t-i»-itoiO00COOx^1 
QOOcOOt-'tOCO>4:».C;i--lCDtsDa>>-*cDtOOO 

•^ibOGDOii>3H-h-'co^c;<oac?iOc;^wcn-^ 



00 
05 



I 



428 



HAND-BOOK OF LAND AND MARINE ENGINES. 



05rf*'b000005>*i'tOOQ005>^t-COOOOi><i^ 


Length 
in Feet. 


1— » (-J l_a l_J bO bO *>- 


CO 


1 

CD 

P' 

P 
O 

P* 

P 


H-i t-a H_i tsD 05 


to 


iigiiiiigsigsiiil 




isiiiiiiBigsilii 


OP 


fc0^ctOlotofcocoo^co^^*^otOi^^cotOGo 


to 


l-i|-ifcOtObOtOtOfcCCOCO*.4i-CTC5iOOOO 

^1 00 o H-i 05 h^ Ci CO in5 <:;« o o-> CO 4^ o -1 O 

QOCD^>^O^OOtOH-^h-'COOiCCCOl— -4 


bO 


sisiiiiiiaiisssii 


to 


SsiSii^miiiSigi 


§ 


O^a)05^OCniN3rf^OlN3WO00rfi.O<:D 


CO 

CO 


^bOC04^0^05-<lSl-iCOOiOOitNDi-*K^^I 

<:D05>^toccc;<Goc;i»*i».ooQ005^iooOMi^i-» 


CO 



HAND-BOOK OF LAND AND MARINE ENGINES. 



429 



BOILER-HEADS. 

There ape two forms of boiler-heads in general use, 
and four ways in which they are secured to the shell of 
the boiler. These are: 1st. The flat head turned outward. 
2d. The flat head turned inward. 3d. The arched head 
turned outward. 4th. The arched head turned inward. 

Considering the two facts, 1st, that, with a given amount 
of material, arched forms are stronger than flat ones, and, 
2d, that cast-iron resists compressive better than tensile 
strains, it plainly appears that the first plan mentioned 
above is the weakest, and the fourth plan, the strongest 
way, a cast-iron head can be used. It is also true that 
either form of head is stronger when turned inward than 
otherwise. 

There is no doubt whatever as to the truthfulness of 
these statements in so far as the strength of the head is 
concerned, but there are other considerations besides 
strength which determine the form of boiler-heads. 




Arched Head turned inwards. 

The first to be considered is the arched head turned in- 
ward — the strongest plan. It will be noticed, that if the 
head is made of uniform thickness, with a curve at the 
spring-line of the arch, as it should be, to secure a sound 
casting, between the head and the sheet an acute angular 
space is left, liable to fill up with sediment and harden 
into scale by the action of the fire, which is usually severe 
at this part of the boiler. 



430 



HAND-BOOK OF LAND AND MARINE ENGINES. 



Experience has shown that the boiler-plates at this 
point have corroded and burnt out very rapidly with the 
heads made and inserted in this manner, though the action 
of the sediment may be prevented by squaring up the head 
to a right angle with the sheet ; but this renders the plate 
liable to over-heating from the excessive quantity of cast- 
iron in contact with it just over the fire. 



<t^ 



C~) 



Flat Head turned outwards. 

Now there are other objections to inserted heads, such 
as loss of capacity, and the necessity of tap-rivets over the 
water connections, which are more expensive to insert and 
more liable to leak than the usual form of rivets. Some 
of these objections may be overcome by setting the boiler 
far enough ahead in the front to protect the mass of iron 
in the head from the severe action of the fire. 

Now, by adding | more metal, and distributing it evenly 
in thickness all over, and giving the head an arched form, 
it can be turned outward, and possess all the requirements 
of strength needed for safety, and avoid the objectionable 
features of the concave head. 

The flat head turned outward possesses the most ob- 
jectionable features of any other form, as it is the worst 
disposition which can be made of the metal, to stand 
internal elastic pressure. 

Whether boiler-heads be turned inward or outward, it is 
evident that they must possess strength equal at least to 
the metal of the sheet across the transverse rows of rivet- 



HAND-BOOK OF LAND AND MARINE ENGINES. 



431 



holes, as the section of metal after punching is the measure 
of strength in any boiler without stays. 



{ti 




c=^) 



Arched Head turned outwards. 



While we can assume that the head loses the same 
amount of metal, by the rivet-holes, proportional to its 
thickness that the sheet does to which it is secured, what- 
ever be the size or number of rivets, we have but to con- 
sider, in the comparison of strength, the ratio of thick- 
ness of head and sheet and the tensile strength of each 
material. 

Wrought-iron heads of the flat, arched, and egg-shaped 
forms are now very generally used on account of their great 
tensile strength, lightness, and the facilities they afford to 
bracing, more particularly for boilers of large diameters. 




SAFETY-VALVES. 

The form and constpuotion of this indispensable adjunct 
to the steam-boiler are of the highest importance, not only 



432 HAND-BOOK OF LAND AND MARINE ENGINES. 

for the preservation of life and property, which would, in 
the absence of that means of "safety," be constantly 
jeopardized, but also to secure the durability of the steam- 
boiler itself 

And yet, from the manner in which many things called 
safety-valves have been constructed of late years, it would 
appear that the true principle by which safety is sought 
to be secured by this most valuable adjunct, is either not 
well understood, or it is disregarded by many engineers 
and boiler-makers. 

Boiler explosions have in many cases occurred when, 
to all appearance, the safety-valves attached have been 
in good working order; and juries, under the presidency 
of coroners, have not un frequently been puzzled, and 
sometimes guided to erroneous verdicts, by scientific evi- 
dence adduced before them, tending to show that nothing 
was wrong with the safety-valves, and that the devastating 
catastrophies could not have resulted from over-pressure, 
because in such case the safety-valve would have prevented 
them. 

It is supposed that a gradually increasing pressure can 
never take place if the safety-valve is in good working 
order, and if it have proper proportions. Upon this 
assumption, universally acquiesced in, when there is no 
accountable cause, explosions are attributed to the " stick- 
ing " of the valves, or to " bent " valve-stems, or inopera- 
tive valve-springs. As the safety-valve is the sole reliance 
in case of neglect or inattention on the part of the en- 
gineer or fireman, it is important to examine its mode of 
working closely. 

The safety-valve is designed on the assumption that it 
will raise from its seat under the statical pressure in the 
boiler, when this pressure exceeds the exterior pressure on 
the valve, and that it will remain off its seat sufficiently 



HAKD-BOOK OF LAND AND MARINE ENGINES. 



433 



far to permit all the steam which the boiler can produce 
to escape around the edges of the valve. The problem 
then to be solved is, What amount of opening is necessary 
for the free escape of the steam from the boiler under a 
given pressure ? 

The area of a safety-valve is generally determined from 
ideas based on the velocity of the flow of steam under dif- 
ferent pressures, or upon the results of experiments made 
to ascertain the area necessary for the flow of all the 
steam a boiler could produce under a given pressure. But 
as the fact is now generally recognized by engineers that 
valves do not rise appreciably from their seats under 
varying pressures, it is of importance that in practice the 
outlets around their edges should be greater than those 
based on theoretical considerations. 

The next point to be considered is how high any safety- 
valve will rise under the influence of a given pressure. 
This question cannot be determined theoretically, but has 
been settled conclusively by Burg, of Vienna, who made 
careful experiments to determine the actual rise of safety- 
valves above their seats. His experiments show that the 
rise of the valve diminishes rapidly as the pressure 
increases. 

TABLE 

SHOWING THE EISE OF SAFETY VALVES, IN PARTS OF AN INCH, 
AT DIFFERENT PRESSURES. 



Lbs. 

12 


Lbs. 
20 


Lbs. 
35 


Lbs. 
45 


Lbs. 
50 


Lbs. 
60 


Lbs. 
70 


Lbs. 
80 


1 

Lbs. 
90 



Taking ordinary safety-valves, the average rise for press- 
ures from 10 to 40 pounds is about ^'^ of an inch, from 
37 2C 



434 



HAND-BOOK OF LAND AND MARINE ENGINES. 



40 to 70 pounds about ^'q, and from 70 to 90 pounds about 
y4 of an inch. 

The following table gives the result of a series of experi- 
ments made at the Novelty Iron- Works, New York, for 
the purpose of determining the exact area of opening 
necessary for safety-valves, for each square foot of heating 
surface, at different boiler pressures. 



TABLE. 



a a» 


o o f 


fl © 


OP O 1 


p ® 


o o ^ 


-5 


5s ?3 =J 


-5 


^Ss 


°5 


e« ^ S 




S 305 




S :2a3 




s ::a2 




CT'Cr 


© 


0*0* . 


Q 


crcr" 


il. 


rifice in s 
r each s 
Heating 


o > 

.2 5 


rifice in s 
r each s 
Heating 




rifice in s 
r each s 
Heating 


Hi 


o^^ 


-|o 


£^o 


£|§ 


£•2^ 


|ll 


^ '^ 9 ^ 




g.2^1 






<"^ 


^ 


<1 


p. 


<: 


0.25 


.022794 


10 


.005698 


70 


.001015 


0.5 


.021164 


20 


.003221 


80 


.000892 


1 


.018515 


30 


.002244 


90 


.000796 


2 


.014814 


40 


.001723 


100 


.000719 


8 


.012345 


50 


.001398 


150 


.000481 


4 


.010582 


60 


.001176 


200 


.000364 


5 


.009259 











The experiments were made on a tubular boiler with 
no means of escape for the steam except the safety- 
valve. 

If we compare the area of openings, according to these 
experiments, with Zeuner's formula, which is entirely theo- 
retical, it will be observed that the results from the two 
sources are almost identical, or so nearly so as not to 
make any very material difference. 

In the absenc;^ of any generally recognized rule, it is 
customary for engineers and boiler-makers to proportion 
safety-valves according to the heating surface, grate sur- 



HAND-BOOK OF LAND AND MAEINE ENGINES. 



435 



% 



TABLE 



OF COMPARISON BETWEEN EXPERIMENTAL RESULTS AND THEO- 
RETICAL FORMULA. 



Boiler Pressure, 45 Pounds. 


Boiler Pressure, 75 Pounds. 


Heating 
Surface. 


Area of 
Opening 
found by- 
Experi- 
ment. 


Area of 
Opening 

according 
to 

Formula. 


Heating 
Surface. 


Area of 
Opening 
found by 
Experi- 
ment. 


Area of 
Opening 

according 
to 

Formula. 


Sq. Ft. 

100 

200 

500 

1000 

2000 

5000 


Sq. Inches. 

.089 

.180 

.45 

.89 
1.78 
4.46 


Sq. Inches. 
.09 
.19 
.48 
.94 
1.90 
4.75 


,Sq. Ft. 

100 

200 

500 

1000 

2000 

5000 


Sq. Inches. 

.12 

.24 

.59 
1.20 
2.40 
6.00 


Sq. Inches. 

.12 

.24 

.59 
1.18 
2.37 
5.95 



face, or horse-power of the boiler. While one allows 1 inch 
of area of safety-valve to 66 square feet of heating surface, 
another gives 1 inch area of safety-valve to every 4-horse 
power; while a third proportions his by the grate sur- 
face, — it being generally the custom in such cases to allow 
1 inch area of safety-valve to If square feet of grate 
surface. 

Experiments are very much needed to determine the 
proportions of safety-valves that would be capable of lib- 
erating all the steaim which a boiler might produce with 
the fires in full blast, and all other means of escape 
closed. Until such a safety-valve shall be devised and 
adopted into general use, safety from gradually increasing 
pressure must depend to a certain extent on the watchful- 
ness of engineers and firemen. 

The safety-valve has not heretofore received that atten- 
tion from engineers and inventors which its importance as a 



436 HAND-BOOK OF LAND AND MARINE ENGINES.* 

means of safety deserves. In the construction OT^uTother 
kinds of machinery, continual efforts have been made to 
insure accuracy ; while in the case of the safety-valve, very 
little improvement has been made either in design or fit- 
ting. It is difficult to see why this should be so, when it is 
known that deviations from exactness, though small in 
themselves, when multiplied, become not only detrimental 
to the free action of the valve, but actually endanger the 
safety of the boiler. 

Safety-valves should never be made with rigid stems, 
as, in consequence of the inaccuracy of other parts of the 
fitting, the rigid stem has a tendency to prevent the valve 
from adjusting itself on the seat, thereby causing leakage ; 
as a remedy for which, through ignorance or want of skill, 
they are often jammed or overweighted, the stems being 
frequently bent, thus rendering the safety-valve a source 
of danger rather than a means of safety. 

It is advisable, in all cases, to have the seating of safety- 
valves as narrow as the varying modes of construction will 
permit, as, with a wide seating, they are more liable to 
" stick," and more difficult to repair when leaky or out of 
order. 

Safety-valve levers should, in all cases, be as short as 
the ordinary working pressure will permit. 

Safety-valve levers should, in all cases, be moved before 
the fire is started under the boilers, in order to ascertain 
if the valves are in working order. 

The safety-valve should never be raised when the water 
is dangerously low in the boiler. 

All compound or complicated safety-valves should be 
avoided, as any interference with the direct action of the 
valve and lever has a tendency to render them unreliable. 

The safety-valve should only be regarded as a means of 
safety when well proportioned, well constructed, and well cared 
for after being put in use. 



HAND-BOOK OF LAND AND MARINE ENGINES. 439 

Rule jor finding Centre of Gravity of Taper Levers for 
Safety-valves. — Divide the length of lever by two (2) ; 
then divide the length of lever by six (6) and multiply 
the quotient by width of large end of lever less width of 
small end, divided by width of large end of lever plus 
width of small end. Subtract this product from the first 
quotient, and the remainder will be the distance in inches 
of the centre of gravity from large end of lever. 

EXAMPLE. 

Length of lever 36 inches. 

Width of lever at large end 3 " 

Width of lever at small end 2 " * 

36 -^ 2 =^ 18 — 1-2 =1 16-8 inch. 36--6 = 6Xl-=6^5 = 1-2. 
Centre of gravity from large end, 16*8 inches. 

FOAMING. 

The tendency of the water in a steam-boiler to rise into 
the cylinder is well known to engineers, and is generally 
attributed to the presence of dirt, grease, and other soapy 
substances; but, under certain circumstances, might be 
attributed to an insufficiency of steam room in the boiler, 
which would induce foaming, however clean the water 
might be. 

Foaming is promoted, if not actually caused, by the 
reduction of pressure, and consequent ebullition of the 
water immediately below that point of the boiler whence 
the steam is drawn, which disposes the water, in the form 
of spray, to be carried along with the ascending current 
of steam. Not only is the water thus carried into the steam- 
pipe, but also any particles of earthy and other foreign 
matter that may happen to be at the broken surface of the 
water. 

In analyzing the various causes concerned in the pro- 



440 HA^'D-BOOK OF LAND AND MARINE ENGINES. 

duction of foaming, it is necessary to take into considera- 
tion the effects produced by the necessarily intermittent 
action of the steam-valves. The supply of steam to the 
cylinder being cut off for a considerable period during 
each stroke, the effect is to throw the water in the boiler 
into a slight undulatory motion, as may frequently be 
observed in the glass water-gauge. 

Foaming is also probably due in some measure to the 
flow of steam to the point of escape, carrying particles of 
water along with it by the induced current it produces. 

The three most common causes of foaming are insuf- 
ficient steam room, foulness of boilers, and excessive firing. 
Various expedients have been resorted to, such as perforated 
pipes, baffle-plates, etc., without any very beneficial effect ; 
but experience has shown that the most practical and most 
reliable preventives of foaming are ample steam room, 
clean boilers, and moderate firing. 

Foaming in locomotive boilers is generally caused by 
impurities in water, which are confined to certain parts 
of the country known as the alkali regions ; these impuri- 
ties are composed essentially of potash, soda, ammonia, 
and lithia. Locomotive boilers using surface water are 
also apt to foam if allowed to become dirty, in consequence 
of decayed vegetable matter held in suspension in the water, 
because such sedimentary accumulations add to the strength 
of the ingredients above referred to. 

Foaming in marine boilers not unfrequently arises from 
insufficiency of steam room, as at each stroke of the engine 
a great portion of the steam is taken out, and as a result 
the pressure is lessened to such an extent as to induce vio- 
lent foaming. Foaming is also inherent in some types of 
boilers, in consequence of their peculiar construction pre- 
venting a free escape of the steam from the heating sur- 
face to the steam room. 



HAND-BOOK OF LAND AND MARINE ENGINES. 441 

Foaming in marine boilers is most generally caused by 
changing the water from salt to fresh, or from fresh to 
salt; and is made evident by the boiling up of the water in 
the glass gauge. When foaming occurs from this cause, 
it is desirable to change the water in the boiler, and make 
it all of one kind, either salt or fresh, as soon as possible ; 
and in order to do this, it is necessary to put on a strong 
feed and blow out slowly and continually, or at short 
intervals, until the water is changed. 

It sometimes becomes necessary, when the foaming is 
very violent, to throttle down the steam, cut off short by 
means of the link, or even stop the engine, in order to ascer- 
tain the level of the water in the boilers, as it will always 
be found to be higher when the engine is in motion than 
when standing still. 

It frequently occurs that, when the engine is stopped to 
suppress foaming, the water has fallen considerably be- 
low the proper level ; under such circumstances, it is always 
better to dampen the fires, and start the independent feed- 
pump and pump in a fresh supply of water. 

Boilers with a large amount of heating surface and 
small steam room generally foam ; so also do boilers with 
the ordinary amount of steam room, if the water be carried 
too high. 

All the phenomena connected with foaming have not 
yet been satisfactorily explained ; but, from whatever cause 
it may arise, it is always attended with a certain amount 
of danger. 

INCRUSTATION IN STEAM-BOILERS. 

Most waters used for stationary and locomotive boilers 
contain solid matters in solution which become precipitated 
by elevation of temperature, or are left behind by cvapora- 



442 HAND-BOOK OF LAND AND MARINE ENGINES. 

tion. On the matters ceasing to remain in solution, the 
first effect will be their deposition, and unless blown out 
sooner or later, the deposit becomes hardened and forms 
incrustation. The quantity of matters held in solution are 
commonly from 20 to 30 grains per gallon, and in some 
few cases reach as much as 100 grains per gallon. 

The mere amount of solid matter in any water is no in- 
dication of its fitness, or otherwise, to be used in a steam- 
boiler, as this depends almost entirely on the nature of the 
solid impurities contained. 

The presence of 50 grains per gallon of deliquescent 
salts — such, for example, as carbonate or chloride of soda 
— would not be seriously felt with a moderate amount of 
attention to blowing off; whereas, on the other hand, an 
equal quantity of salts of lime would render the water 
unfit for use, unless an unusual amount of care and atten- 
tion were bestowed on blowing out and cleaning the boiler. 
Unfortunately, the presence of the former description of 
«alts is the exception, whilst the latter is the rule. 

It is generally understood that the carbonate of lime — 
the same substance, chemically speaking, as selenite, chalk, 
marble, and limestone — is held in solution in fresh water 
by an excess of carbonic acid, and that in reality it is 
present in the state of a bicarbonate. By heating the 
water, the excess of carbonic acid is driven off, and the 
greater part of the carbonate is precipitated. 

Its solubility diminishes as the temperature increases, 
and at boiling-point it is scarcely soluble at all. It is for 
this reason that in water from which the air has been ex- 
pelled, carbonate of lime is found in such small quantity. 
Carbonate of lime has been variously estimated as soluble 
in from 24,000 to 16,000 times its volume of water at 
ordinary temperature, or in the proportion of from 2| to 
4^ grains per gallon. 



HAISTD-BOOK OF LAISTD AND MARINE ENGINES. 443 

Sulphate of lime, a substance of the same chemical com- 
position as gypsum, or plaster of Paris, is next in import- 
ance to carbonate of lime. Its solubility also varies greatly 
with the temperature; its greatest solubility is at 95^ Fah., 
when it dissolves in 393 times the weight of water, or in 
the pi'oportion of 178 grains to the gallon. At 212° it is 
only soluble in 460 times its weight of water, or 152 grains 
to the gallon ; like carbonate of lime, it is completely in- 
soluble at about 290°. It is, therefore, evident that these 
two salts are precipitated in all kinds of water merely by 
the elevation of temperature, when the boiler is worked at 
about 60 pounds pressure. 

In boilers working at a low pressure, the sulphate of 
lime could be partially extracted by blowing off, if the 
water became saturated with it at about 230° ; but its 
solution requires time, and the rapid evaporation precip- 
itates it more rapidly than it can redissolve. 

Carbonate of magnesia, or magnesian limestone, is the 
next important impurity in fresh water; but it usually 
exists in much smaller quantities than the other two salts. 
On its relation to temperature, and in its behavior in the 
water, it is similar to carbonate of lime. 

On becoming insoluble, the lime and other salts remain 
for a time suspended in the water, and tend to deposit 
themselves more or less rapidly, according to the density 
of the water, the manner in which it circulates, and the 
intensity of the ebullition. 

Over those parts of the heating surface where the water 
boils rapidly, the insoluble salts are held in suspension by 
the agitation until the ebullition subsides ; or, when the 
circulation is good, they are carried away with the currents 
until a comparatively quiet part of the boiler is reached, 
when they are deposited on the plates and tubes. 

The manner in which the precipitation comes about 



444 HAND-BOOK OF LAND AND MARINE ENGINES. 

is sometimes very remarkable, especially when the feed- 
water, at a high temperature, enters the boiler nearly at 
the point of saturation. In such cases the lime-salts are 
deposited as they pass through the apertures in the feed- 
pipe, and gather fast and thick on the adjacent plates. 

It is by many supposed that the plates over the furnaces 
are most liable to become covered with a thick incrusta- 
tion, as the greatest quantity of water is here evaporated. 
This is, however, seldom or never found to be the case, 
unless the circulation is very bad, as, for instance, over the 
flat, stayed crowns of locomotive fire-boxes. 

In plain cylindrical and internally fired tubular boilers, 
the suspended matters in the water are driven off the 
plates by the ebullition, and carried to the part of the 
boiler where the circulation is most feeble, or the coolest 
part of the boiler. 

When a considerable amount of incrustation is found 
over the fire in ordinary externally fired boilers, it is 
usually caused by the detached scale, which has fallen 
from the sides of the shell in pieces too heavy to be carried 
away by the circulation. The danger of overheating from 
this cause is one of the principal arguments against the 
practice of having a fierce heat under a boiler-shell, where 
the nature of the incrustation renders it liable to cover the 
furnace plates to any great degree. 

The carrying away of the deposited matter by the 
ebullition and circulation is also retarded by the presence 
of grease or sticky matters in the water, which form a 
part with the impurities, that often prove too heavy or 
tenacious for removal by the currents in the boiler. 

The sulphate of lime on depositing forms an amor- 
phous crust more or less hard, according to the other 
ingredients in combination with it, and the heat to which 
it is exposed. The carbonate of lime and carbonate of 



HAND-BOOK OF LAND AND MARINE ENGINES. 445 

magnesia, on the other hand, usually deposit a loose, fine 
powder, forming a white sludge with the water. 

When the deposited carbonate of lime is present in con- 
siderable quantity along with other impurities, it will 
remain soft for a length of time, and, if not exposed to too 
high a temperature when drying or emptying the boiler, 
will be converted into a floury powder of a light color. 
But if the boiler be blown out while the plates and brick- 
work in the flues are at a high temperature, the sludge 
often becomes baked hard ; and it is to this circumstance 
that a great amount of the hard incrustation from both 
the sulphate and carbonate of lime is due. 

When a boiler fed with water containing salts of lime 
is blown out cold, and the interior is examined before it 
becomes dry, the plates, tubes, and stays may be found 
covered with a thick coating of light-colored slushy matter, 
that can be removed with very little trouble if brushed 
off* or washed out with a hose-pipe and jet of water. 
Should, however, the interior be maintained at a high 
temperature by blowing out before the boiler and flues are 
cool, the deposit becomes baked on, and apparently there 
is not so much left for removal. 

Various attempts have been made to calculate the loss 
of heat caused by incrustation formed on the heating 
surface. But the circumstances to be considered which 
determine the rate of heat transmission through plates 
covered by scale of different kinds and thickness, either 
homogeneous or otherwise, are not sufficiently well under- 
stood, and are too numerous to admit of anything like 
exact calculation. But it has been very satisfactorily 
proved by observation and experiment that j'^ inch of in- 
crustation on the tubes of a boiler is equivalent to a loss 
of 20 per cent, of fuel, and that the loss increases in a very 
rapid ratio. 
38 



446 HAND-BOOK OF LAND AND MARINE ENGINES. 

It frequently happens that no two of the numerous layers 
are alike in color, consistency, or chemical composition, — 
a fact due to the disturbing influence at the source of the 
feed supply. The face of the incrustation next to the plate 
is very often of a black color, and adhering to it is found 
a film of oxide of iron, whilst the surface of the plate is 
quite soft, and bears unmistakable signs of wasting, some- 
times to a considerable depth. This is usually caused by 
the corrosive action of the iron salts, and in brackish 
water by chloride of magnesia (muriate of magnesium). 
This last salt is the destructive agent in sea-water. 

From water containing salts of iron in considerable 
quantity the incrustation formed has often a red tinge. 
Chalybeate waters are generally highly injurious to the 
plates, and the film of incrustation next to the iron is 
sometimes of a deep red, coloring the water that comes in 
contact with it through the fissures in the scale, by which 
the presence of these injurious salts of iron is easily 
detected. 

When the water in a steam-boiler becomes impregnated 
with the above-named ingredients, great resistance is 
offered to the free escape of the steam bubbles and to the 
free convection of heat. The water is, in consequence, 
lifted off the plates by the steam that accumulates on their 
surface, and allows them to become over-heated. 

The tendency to over-heating is much aggravated, if 
grease or other organic matter be present in the \tater 
along with this floury deposit. The grease appears to 
combine mechanically with the carbonate of lime, and 
when the compound sinks on to the plates over night, or 
when the boiler is at rest, it clings as a loose, spongy mass, 
too inert to be carried off by the circulation or ebullition 
which it retards, and by preventing the contact between 
the plates and the water, and by offering great resistance 



HAND-BOOK OF LAND AND MARINE ENGINES. 447 

to the transmission of heat, produces over-heating of the 
plates. 

There are but few problems connected with steam en- 
gineering at which inventors have tried their hands to a 
greater extent, than the prevention and removal of boiler 
incrustations. Numerous inventions, and not less than 
three hundred patents, have been taken out for that pur- 
pose, but most of them have proved futile, — some because 
their inventors did not fully comprehend the magnitude 
of the object involved, and others on account of the diver- 
sity of conditions and circumstances under which they 
have been tried. 

The substances used to act mechanically in prevent- 
ing and removing incrustation by decreasing the cohesion 
and adhesion of the deposited particles, are even more 
numerous than those employed to act chemically in de- 
composing and dissolving the solid matters. In fact, it is 
difficult to mention any common commodity that has not 
been employed to prevent incrustation in one way or the 
other, although the manner in which different substances 
may act is often not understood by those who employ them. 

The following chemical and mechanical remedies have 
been proposed at different times for the removal and pre- 
vention of scale in steam-boilers : 

Frequent blowing off. 

Employment of some collecting apparatus. 

Thorough circulation of the water in the boiler. 

Purification of the water before entering the boiler. 

Cracking off the scale by expansion. 

Employment of galvanic batteries or electric anti-crus- 
tators. 

Soda-ash, caustic soda, potash, chloride of barium, cate- 
chu, nut-galls, slippery elm, bass-wood, potatoes, tallow, 
starch, linseed-oil, molasses, pork, Indian meal, etc. 



448 HAND-BOOK OF LAND AND MARINE ENGINES. 

But all of these have been abandoned as worthless, as 
it was found that their action on different boilers, in the 
same locality and using the same water, produced results 
of an entirely different character ; for, while some remained 
comparatively free from scale, others were affected to such 
a degree as to limit their durability and usefulness. 

It is a common occurrence to hear engineers and steam 
users declare that by the use of certain articles they were 
comparatively relieved from the danger and inconvenience 
of incrustation in their steam-boilers, while others, in the 
some locality and under like circumstances, used the same 
remedies without any very satisfactory results. 

Nevertheless, of late years, solvents have been intro- 
duced, not only for the neutralization and removal of old 
scale, but also for the prevention of new. Lord's patent 
boiler compound has been used for the past five years in 
different parts of the country, and under varying circum- 
stances, with eminent success ; it seems to possess the neces- 
sary ingredients to produce satisfactory results under all 
the circumstances, such as water, locality, management, etc. 

This substance, it is stated, will convert the scale-form- 
ing material into insoluble oxalates, which, in the form 
of fine sediment, are retained in suspension, and are readily 
blown out when blowing off the boiler. It is also said to 
have no injurious action upon the iron of boilers in which 
it is used, but, on the contrary, to have a tendency to pre- 
serve the iron. The entire confidence of the manufacturer 
in its effectiveness is shown by the fact that he asks no 
pay until it gives satisfaction. 



HAND-BOOK OF LAND AND MARINE ENGINES. 449 

INTERNAL AND EXTERNAL CORROSION OP STEAM- 
BOILERS. 

Internal and external corrosion are the two maladies 
that boilers are most liable to suifer from. 

Internal corrosion presents itself in various forms, each 
having a peculiar character of its own, though only some- 
times strongly marked; these are designated as imiform 
corrosion^ wasting, pitting, honey-combing, and grooving. 

External corrosion is said to be due to galvanic action, 
or the influence of chemicals and dampness combined. 

By uniform corrosion is meant that description of wast- 
ing of the plates or tubes, where the water corrodes them, 
in a more or less uniform manner, in patches of consider- 
able extent, and where there is usually no well-defined 
line between the corroded part and the sound plate. 

The presence of this as well as other kinds of cor- 
rosion can generally be easily detected, even when covered 
with a considerable thickness of incrustation, as its presence 
is often revealed on emptying the boiler by the bleeding, 
or red streaks, where the scale is cracked ; although in 
some cases, even where the plates are free from incrusta- 
tion, uniform corrosion, in consequence of its even surface 
and the absence of any well-defined limit to its extent, may 
sometimes escape detection. 

Even when actually discovered, the depth to which it 
has penetrated can only be ascertained by drilling holes 
through the plate and measuring the amount of material 
remaining. With lap-joints, the thickness remaining at 
the edge of the plate and round the rivet-heads may serve 
as a guide to the amount of wasting ; but this may prove 
treacherous;, since the adjacent plates may both be cor- 
roded to an equal extent along with the rivet-heads, which 
38^ 2D 



450 HAXD-BOOK OF LAND AND MARINE ENGINES. 

will give the edge of the plate the appearance of having 
the original thickness. 

Another peculiarity worthy of notice is the different 
manner in which the plates and rivet-heads are affected 
by different kinds of waters after the wasting has been 
going on for some time. In most cases the corroded iron 
is readily removed, if it does not come off without means 
being taken to detach it. But cases are to be met with 
where the corroded iron adheres tenaciously to the sound 
plate beneath. In such cases considerable force is required 
to remove it, and the presence of the corrosion is not 
suspected until the hammer or pick is forcibly applied. 

It frequently occurs that in the case of two boilers alike 
in every respect, fed with the same water, and subject to 
the same treatment, one may be found attacked at the 
front end, whilst the other may be affected only on the 
bottom at the back end. 

With the feed -water from one supply only, corrosion 
is found more often under an incrustation of sulphate of 
lime than under one consisting chiefly of carbonate of 
lime. In many boilers fed with water containing the 
former salt, a coating of oxide of iron of a black color 
may be found adhering to the detached scale, which, as 
often as it reforms and is broken off, brings with it a fresh 
film of oxide. 

Various means, such as the use of rain, surface, and 
distilled waters, have been employed for the prevention of 
internal corrosion, but were found impracticable and 
generally abandoned, as the expense involved in most 
cases was found to exceed that of replacing the corroded 
boiler with a new one, even after a service pf only a few 
years. * 

Lord's Boiler Compound appears to be the only known 
remedy that affords any protection to boilers against the 



HAND-BOOK OF LAND AND MARINE ENGINES. 451 

fearful effects of this singular and mysterious phenomena, 
as it has been found to neutralize the mineral ingredients 
of the most destructive waters, and prevent the internal 
corrosion and wasting of boiler-plates, seams, and rivets. 

External corrosion is frequently more destructive than 
internal, particularly in the case of stationary boilers. 
This probably arises from the fact that its presence is 
less suspected, and is often less easily detected in conse- 
quence of the covering of brickwork or other material 
surrounding the shell. 

The most frequent sources of external corrosion are, 
exposure to the weather, leakage from seams, dripping 
from safety or other valves, moisture rising from the 
ground, either from the damp nature of the location or 
from the want of proper appliances to carry off the waste 
water. 

A slight leakage from a bad joint may be sufficient to 
cause a severe local grooving at the seam or flange, as it 
often goes on for a length of time unperceived and unsus- 
pected, especially when the shell is covered by brickwork, 
or other material to prevent the radiation of heat, as in 
such cases, if a leak takes place on the upper side of the 
boiler, the whole circumference of the shell is liable to 
suffer from it. 

One of the most remarkable circumstances connected 
with all kinds of corrosion is the singular manner in 
which they make their appearance and act, affecting very 
few boilers alike, or even in the same locality. 

Coprosion of Marine Boilers. — Marine boilers seldom 
last more than four or five years; whereas land boilers, 
made of the same quality of iron, often last fifteen or 
twenty years ; yet the difference in durability is not the 
effect of any chemical action upon the iron by the contact 
of sea-water, for the flues of marine boilers rarely show 



452 HAND-BOOK OF LAND AND MARINE ENGINES. 

any deterioration from this cause ; and even in worn-out 
marine boilers, the hammer-marks on the flues are as con- 
spicuous as at the time of their formation. 

The thin film or scale spread over the internal parts of 
marine boilers would seem of itself to preserve that part 
of the iron from corrosion which is situated below the 
water-level ; but, strange as it may seem, it is rare to find 
any internal corrosion of boilers using salt-water, in those 
parts of the boiler with which the water comes in contact ; 
the cause, therefoi:e, of the rapid corroding of marine 
boilers is not traceable to the chemical action of salt-water, 
as steamships provided with surface condensers, which 
supply the boilers with fresh water, have not reaped much 
benefit in the durability of their boilers. 

Corposion of steam-boilers is one of the most obscure 
subjects in the whole range of engineering. 

BOILER EXPLOSIONS. 

That the use of steam-power is fraught with danger 
is only too well known ; the extent of the danger, however, 
as indicated by the number of boiler explosions every 
year, and the loss of life and property entailed, is but 
vaguely appreciated by the public at large. No oflicial 
record is kept of such accidents, and only those of excep- 
tional interest are reported in the newspapers. Even in 
such cases as are reported, it is almost impossible to 
ascertain their true cause, as there is seldom a unanimous 
opinion on the part of the experts who examine into the 
causes after the event. 

There are a great many people who think they know 
something that will explain the cause of these fearful 
accidents, but, for some reason or other, their fine-spun 
theories have been of no practical value. One reason 



HAND-BOOK OF LAND AND MARINE ENGINES. 



453 




The above cut represents the explosion of a portable boiler at an 
excavation in New York city. The boiler had been fourteen years in 
use, and was never known to have been cleaned or tested. For a long 
time before the explosion occurred, the safety-valve and steam-gauge 
were out of order, the glass water-gauge was allowed to fall into 
disuse, and the gauge-cocks were filled with mud. 



454 HAND-BOOK OF LAND AND MARINE ENGINES. 

for this is, doubtless, that the conditions under which 
experiments have been made to determine the causes of 
explosions are entirely different from those under which 
boilers are used. Some points may be settled by experi- 
ment, such as the strength of the material of which boilers 
are constructed ; but even here there is room for error, inas- 
much as the conditions under which experiments are made 
on iron and steel are very different from those under 
which boilers are torn to pieces by explosion. 

Formerly, the impression was almost universally enter- 
tained by steam users and the public that boiler explo- 
sions were induced by certain mysterious causes, such as 
electricity, generation of explosive gases within the boiler, 
caused by the decomposition of steam ; instantaneous 
flashing of large bodies of water into steam, which were 
attempted to be explained by the spheroidal theory; 
great deterioration in the quality of the plates, caused by 
mysterious chemical changes, concussive ebullition, etc. 

An unwillingness to know the true cause of explosions, 
on the part of steam users or those most interested, as well 
as an inability on the part of the authors of the above 
enumerated mysterious and occult causes to explain them 
satisfactorily, has no doubt been the means of perpetuating 
much of the nonsense that has been promulgated on this 
subject. 

The following remarks are submitted for the purpose 
of showing the fallacy of the above theories, and also to 
direct the attention of engineers and steam users to the 
actual sources of danger. 

Electricity might be developed in a steam-boiler under 
certain conditions ; but it is difficult to conceive how any 
quantity could be accumulated, as Faraday, the eminent 
chemist, has proved that the development of electricity in 
a vessel containing steam was due solely to the friction of 



HAND-BOOK OF LAND AND MARINE ENGINES. 455 

the steam against the sides of the vessel. Such being the 
case, the presence of electricty would be most likely to occur 
in the pipe between the boiler and the engine, and would be 
induced by the friction of the escaping current ; but even 
in that case, the steam must be wet, as the same authority 
proved that electricity could not be developed from a cur- 
rent of dry steam. 

Admitting that the presence of electricity in an ordi- 
nary boiler is not impossible, it yet remains to be shown 
that it could exist in a state of high tension ; and yet, again, 
how it could bring about an explosion, accompanied by 
the usual well known results. 

Concussive Ebullition. — The phenomena called concus- 
sive ebullition, arises, according to Dufour, from the prin- 
ciple, that in order that a liquid may be transformed to 
vapor at any temperature, some portion of the surface 
must be freely exposed to a space into which the vapor 
may expand. This was demonstrated by suspending drops 
of water in heated oil. The temperature of the water was 
raised considerably above the boiling-point without the 
formation of vapor ; but if a bubble of air or a piece of 
porous substance was placed in contact with the water, a 
burst of vapor occurred. But experiments with drops of 
oil or drops of water can, at best, shed but very feeble light 
on the causes of boiler explosions, as experiments in the 
laboratory are made under very different conditions from 
those to which steam-boilers are daily subjected in mills 
and factories. 

Generation of Explosive Gases. — That a small quan- 
tity of steam might be decomposed in a boiler, by coming 
in contact with plates that have accidentally become red- 
hot, cannot be disputed ; but that the decomposition could 
occur to any considerable extent with oxidized plates is 
wellnigh impossible. The hydrogen liberated by the de- 



456 HAND-BOOK OF LAND AND MARINE ENGINES. 

composition is not explosive, and would require to be 
united and intimately mixed with its equivalent of oxy- 
gen, and then ignited to produce an explosion. 

Supposing the oxygen to be admitted with the feed- 
water, and that the ignition could be, effected by red-hot 
plates or an electric spark, it still remains to be shown 
how the ^ases could possibly become so intimately mixed, 
in the presence of so large a body of steam and nitrogen 
present in the boiler, as to form a detonating compound. 

Again, assuming that nearly all the steam could be de- 
composed, the hydrogen would only burn quietly in the 
presence of oxygen as it becomes liberated on the red-hot 
surface of the plates ; and in any case, its power to pro- 
duce an explosion is extremely improbable. 

But to take the most extreme view of the case, and 
assuming the sudden formation of a vacuum within the 
boiler, by the union of the two gases, to take place, it 
is still by no means clear how the bursting of the shell 
m)uld follow in consequence, as the vacuum formed could 
only be local and insignificant with a large quantity of 
steam and nitrogen in the boiler. 

Spheroidal Theory. — The spheroidal theory is the so- 
claimed tendency of water, when thrown upon highly-heated 
plates, to assume the spheroidal condition and to evapo- 
rate suddenly when the temperature is sufiiciently lowered. 
But the exact application of this theory is, however, by 
no means clear ; and the assumed delay of the water in 
evaporating is antagonistic to the sudden evaporation from 
the overheating theory, as it is difficult to see how the 
evaporation of a large quantity of water in an ordinary 
boiler could be delayed, as is assumed in this theory, 
without reducing the temperature of the water below that 
sufficient to produce an explosion. 

Deterioration of Plates. — This subject admits of no 



HAND-BOOK OF LAND AND MARINE ENGINES. 457 

speculation, as it comes under the head of "wear and 
tear/' which has been discussed in a former article. That , 
the sudden heating or cooling and oxidation of parts of 
the boiler induce a great deterioration of strength has 
been proved by experience, but such evils can only be 
avoided by constant attention and repairs. 

Explosions can occur from one cause only — deficiency 
of strength in the shell or other parts of a boiler. This 
deficiency of strength may be an original defect arising in 
the material or workmanship at the time of construction, 
or, it may be due to deterioration from use, from ordinary 
wear, or from injuries occurring from mismanagement, 
want of attention, and repairs, etc. 

It often happens that boilers are deficient in strength 
for the pressure they are intended to bear, and no ac- 
cumulation of pressure beyond this is necessary to bring 
about their destruction ; the circumstance of a boiler being 
unable to stand its ordinary working pressure may be due 
in part to its original design, and also to the ignoraj^ce 
of those who fixed the pressure it was worked at, its de- 
sign and power of resistance not being fully understood. 

Defects may arise from workmanship or material, whose 
presence in a great majority of cases can be detected by 
proper inspection and testing, but which may, in some 
cases, escape the closest scrutiny, furnishing an additional 
evidence of the degree of watchfulness necessary on the 
part of engineers and those having the c^-re and manage- 
ment of steam-boilers. 

The defects of workmanship are most liable to escape 
detection in tubular boilers and in those of the locomotive 
type, where the inside cannot be examined unless the tubes 
are removed, or the boiler partly taken to pieces. 

Defects of material, such as blisters, lamination, and 
the adhesion of sand or cinders in rolling, can sometimes, 
39 



458 HAND-BOOK OF LAND AND MARINE ENGINES. 

but ntrt^lways, be detected by inspection. Brittleness of 
material, unless it be glaringly bad, can seldom be dis- 
covered by ordinary inspection after the construction of 
the boiler is completed. 

Ovep-pressure. — Boilers are not unfrequently found 
running by the steam-gauge at a certain pressure which is 
regarded perfectly safe ; but when the gauge is examined 
and compared with one known to be correct, it is found to 
be 10, 20, or perhaps, as is sometimes the case, 50 pounds 
out of the way. If a boiler supposed to be running under 
a pressure of 80 pounds is found, in consequence of an un- 
reliable steam-gauge, to be actually running at a pressure 
of 120 to 130 pounds, the limit of safety may have been 
passed, and an accident is imminent, which may occur at 
any moment. 

Ovep-ppessupe may also be caused by the safety-valve 
being recklessly overweighted, by the sticking of the 
valve on its seat, or by the inadequate size of the com- 
munication between the boiler and the safety-valve, and 
also by placing the safety-valve on a branch-pipe between 
different boilers. 

Ovepheating. — There is no doubt that exposure of the 
upper surfaces of flues or the crown of a furnace to the 
intense action of heat, when there is no water upon their 
surfaces to absorb or transfer this heat, is highly injurious 
and destructive to the boiler ; and on this ground alone 
all the devices for regulating or observing the water-level 
are necessary and advisable. 

A boiler may be well-designed and made up of good 
material and first-class workmanship, and yet in a few 
months after being put under steam, it may explode with 
terrible effect. On examining into the cause of the ex- 
plosion, it may turn out that the water which was used, 
made a heavy deposit; that the boiler had not been 



HAND-BOOK OF LAND AND MARINE ENGINES. 459 

cleaned out since it was put in use ; that the fires had 
been fiercely urged and the water driven from the surface 
of the iron ; as a result, the life had been entirely burnt 
out of the sheets directly over and around the fire, there- 
by weakening the boiler and putting it in a dangerous 
condition. 

Overheating may also be due to shortness of water, 
which in turn may be induced by leakage of valves, stojD- 
cocks, mud- or hand-holes below the water-line ; or by ex- 
cessive priming in boilers containing little water; or it 
may be the result of failure in the feed-pipe supply, or 
neglect to start the water at the proper time, or turn it on 
in sufficient quantity. 

Shortness of water may result from the check-valve 
being kept from its seat by dirt, shavings, or straw, lifted 
by the pump from the well or cistern ; under such cir- 
cumstances the pressure in the boiler would force the 
water back under the valve into the pump-barrel, from 
which it would escape if the drip- or pet-cocks were care- 
lessly or inadvertently left open. 

Accumulation of Deposits. — Explosions in many cases 
are the result of the accumulation of deposits in boilers, as 
the deposit not unfrequently takes the form of hard, solid 
incrustation, which prevents the water from absorbing or 
neutralizing the effect of the heat transmitted from the 
fire to the boiler. 

The presence of such deposits is generally manifested 
by leakage at the seams, and bulging of the plates directly 
over the fire, when the boiler may be considered perma- 
nently injured, and liable to explode at any time. 

Excessive Firing. — Excessive firing is also the cause 
of many disastrous explosions, and occurs most frequently 
where the boiler is too small for the engine, or incapable 
of furnishing the required amount of steam, as the intensity 



460 HAND-BOOK OF LAND AND MARINE ENGINES. 

of the fire necessary to generate the desired quantity of 
steam has a tendency to repel the water from the plates. 
The same effect may be produced when there is a great 
disproportion between the grate and heating surfaces, or 
where the heat from a large grate is concentrated on a 
small space. Under such circumstances, the hqat is 
delivered with such intensity as to lift the water from the 
surface of the iron, thereby exposing it to the direct action 
of the fire. Explosions occurring from excessive firing are 
in all cases the result of avarice, ignorance, or a want of 
skill in the care and management of the steam-boiler. 

It has been shown, in the examination of this subject, 
that no amount of theory will prevent boiler explosions, 
nor will any number of experiments in the laboratory or 
on obsolete types of boilers be of any use whatever in 
deciding what was the cause of such an accident, as all 
the conditions under which the boiler exploded must be 
considered, — the material of which they are constructed, 
workmanship in construction, form or type of boiler, setting 
attachments, quality of water used, kind of fuel, and last, 
but by no means least, skill employed in their care and 
management. These are the vital points, and the ones to 
be considered in order to arrive at any approximate 
solution of the cause or causes of steam-boiler explosions. 

Mainly through the operations and researches of the 
Hartford Steam-Boiler Inspection and Insurance Com- 
pany, boiler explosions have been stripped of the mystery 
in which they were to a certain extent enshrouded, and 
ascribed to their true causes; and in view of the 
numerous defects that tend directly and indirectly to pro- 
duce explosions, that are almost daily brought to light by 
the trained inspectors of that Company, the mystery to be 
solved, if there be any mystery connected with boiler ex- 
sions, seems to be why more boilers do not explode, even 
at their ordinary working pressures. 



HAND-BOOK OF LAND AND MARINE ENGINES. 461 

The jBdelity and skill with which the inspections are 
made by that Company, as well as the correctness of the 
theory on which they are based, — a theory which discards 
mysteries in accounting for boiler explosions, — are suffi- 
ciently attested by the almost entire absence of serious 
.accidents in connection with the thousands of boilers of 

i 

I all sorts and conditions that are or hav^e been in their 
care. 

Whenever the yearly reports of the Hartford Steam- 
Boiler Inspection and Insurance Company are collected, 
and given to steam users and the public in book-form, 
they will form one of the finest contributions to the scien- 
tific literature of the country that has ever been hereto- 
fore published, as they will contain an immense amount 
of important and practicable information on the subject 
of steam-boilers and steam-boiler explosions which could 
be obtained from no other source. 

There is no mystery about steam-boiler explosions ; they 
are all cause and efiect ; and it w ill be found, on investiga- 
tion, that seven- tenths of all the boiler explosions that 
occur yearly in this country might be traced to some 
sufficient cause, were all the facts known. And every at- 
tempt to ascribe boiler explosions to obscure and mysterious 
causes can only be productive of mischief, as they engender 
carelessness on the part of owners and attendants, who are 
often led to believe that no amount of care on their part 
will avail against certain mysterious agents at work within 
their boilers. 



COMPARATIVE STRENGTH OP SINGLE- AND DOUBLE- 
RIVETED SEAMS. 

On comparing the strength of plates with their riveted 
joints, it will be necessary to examine the sectional areas, 
39^ 



462 HAND-BOOK OF LAND AND MARINE ENGINES. 

taken in a line through the rivet-holes witH the section of 
the plates themselves. 

It is perfectly obvious that in perforating a line of holes 
along the edge of a plate, we must reduce the strength ; 
it is also clear that the plate so perforated will be to the 
plate itself nearly as the areas of their respective sections, 
with a small deduction for the irregularities of the press- 
ure of the rivets upon the plate ; or, in other words, the 
joint will be reduced in strength somewhat more than in 
the ratio of its section through that line to the solid sec- 
tion of the plate. 

It is also evident that the rivets cannot add to the 
strength of the plates, their object being to keep the two 
surfaces of the lap in contact. 

When this great deterioration of strength at the joint 
is taken into account, it cannot but be of the greatest im- 
portance that in structures subject to such violent strains 
as boilers, the strongest method of riveting should be 
adopted. To ascertain this, a long series of experiments 
were undertaken by Mr. Fairbairn. 

There are two kinds of lap-joints— single and double 
riveted, as shown in Figs. 1 and 2 on opposite page. In 
the early days of steam-boiler construction, the former 
were almost universally employed ; but the greater strength 
of the latter has since led to their general adoption for all 
boilers intended to sustain a high steam pressure. 

A riveted joint generally gives way either by shearing 
off the rivets in the middle of their length, or by tearing 
through one of the plates in the line of the rivets. 

In a perfect joint, the rivets should be on the point of 
shearing just as the plates were about to tear; but in 
practice, the rivets are usually made slightly too strong. 
Hence, it is an established rule to employ a certain num- 
ber of rivets per lineal foot, which, for ordinary diameters 



HAND-BOOK OF LAND AND MARINE ENGINES. 463 

and average thickness of plate, are about 6 per foot or 2 
inches from centre to centre ; for larger diameters and 
heavier iron the distance between the centres is generally- 
increased to, say 2| or 2^ inches ; but in such cases it is 
also necessary to increase the diameter of the rivet, for 
while I rivets, or even i inch, will answer for small diam- 
eters and light plate, with large diameters and heavy 
plate experience has shown it to be necessary to use f to ' 
I rivets. 

If these are placed in a single row, the rivet-holes so 
nearly approach each other that the strength of the plates 
is much reduced ; but if they are arranged in two lines, 
a greater number may be used, and yet more space left 
between the holes, and greater strength and stiffness im- 
parted to the plates at the joint. . 

Taking the value of the plate, before being punched, at 
100, by punching the plate loses 44 per cent, of its strength ; 
and, as a result, single-riveted seams are equal to 56 per 
cent., and double-riveted seams to 70 per cent, of tlie 
original strength of the plate. F'g' 1. 

It has been shown by very ex- 
tensive experiments at the Brook- 
lyn Navy Yard, and also at the 
Stevens Institute of Technology, 

Hoboken, N. J., that double-riv- 

Fig, 2, 
eted seams are from 16 to 20 per "^ 

cent, stronger than single-riveted 

seams — the material and work- 



r I 



O <i Q Q O 0) O 9 

manship being the same in both / ® ^ ® «> o • <» 



cases. 




Taking the strength of the plate at 100 

The strength of the double-riveted joint would then be 70 
And the strength of the single-riveted joint would be 56 



464 HAND-BOOK OF LAND AND MARINE ENGINES. 

CALKING. 

The object of calking is to bring together the seams of 
a boiler, after riveting, in such a manner that they shall 
be perfectly steam- and water-tight. This is done by using 
a sharp tool ground to a slight angle. The edge of the 
plates being first chipped or planed to an angle of about 
110^, the calking-tool is then applied to the lower edge of 
the chipped or planed angle in order to drive or upset the 
edge, thus bringing the plates together, and rendering the 
joint to all appearances perfectly steam-tight and able to 
resist the internal pressure brought to bear upon this 
particular point. 

It is w^ell known that the use of a hammer on wrought- 
iron will granulate, or harden, it to such an extent as to 
make it almost as hard as steel. Now the angled tool before 
mentioned, through its action, in the process of calking, 
upon the lower edge of the chipped plate, causes a granu- 
lation of that plate ; while the under one is much softer, in 
consequence of not being exposed to the action of the tool, 
consequently, the skin or outer surface of the softer material 
is indented or cut. 

A boiler may be constructed by parties of high repute, 
and be made of the best material, and to all appearance be 
capable of standing any test that can be applied to prove 
its safety, and yet its durability may be very limited, or it 
may collapse or explode soon after being put in use, for the 
simple reason that a cause existed from the v.ery first 
which could not be seen, nor any test point out, and that 
cause was the grooving or indentation made by the calk- 
ing, which became larger and larger through corrosion, 
expansion, and contraction, thus rendering the plates un- 
fit to resist the strain, which must eventually induce 




HAND-BOOK OF LAND AND MARINE ENGINES. 465 

rupture or explosion, resulting in loss of life and destruc- 
tion of property. 

This tendency to weaken the plates of steam-boilers by 
the present mode of calking may be illustrated by very 
familiar examples. 
When a blacksmith de- 
sires to break his bar 
of iron to a given length, 
he first cuts around the 
bar, weakening it ; the 
breaking is then easily 

^ ' ^ . Old-fashioned method of calking, 

zier similarly uses his 

diamond. These illustrations are perfectly analogous to 
that of the cutting or indentation made by the old-fashioned 
calking-tool. 

On examination, steam-boilers are frequently found to 
be fractured along the edge of the outer lap of the sheet 
both transverse and longitudinal, in consequence of a 
channel being entirely cut through the skin of the iron by 
the calking-tool, thus rendering the plate weak at the 
point of the greatest strain. The force to act is ever 
present; the iron is already strained, for by bending a 
sheet of iron to make a required circle, the fibres of the 
iron composing the outer circumference must, of necessity, 
be stretched^nd, by imperfect bending, stretched laterally 
as well as longitudinally, while those of that composing 
the inner circumference are upset, and, if badly welded in 
the act of manufacture, pucker, thereby exposing the in- 
side particles of the iron to the corrosive action of the 
acids in the water, producing a honey -combing. Thus 
everything is ready for the cutting or grooving to be 
made ; the strain on the outer, the puckering on the inner, 

2E 



466 



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HAND-BOOK OF LAND AND MARINE ENGINES. 467 

circumference ; it then only becomes a mere question of 
time as to the result 

Very few, except those familiar with the laws of steam, 
have any idea of the immense pressure exerted on the shells 
of steam-boilers under pressure ; * and when we consider 
that this immense pressure is brought to bear along the lap 
of the joints, — the points deviating farthest from the true 
cylindrical form, — the importance of having the iron not 
only of good quality, but free from the defects induced by 
inferior calking, must at once be admitted. Immense 
sums of money have been expended in experiments with 
the object of ascertaining, if possible, the cause of boiler 
explosions, which, if conducted by competent persons, 
might have proved in many instances to be the result of 
a mischievous system of calkhig. 

The cut on opposite page represents an iir« proved method 
of calking, which is acknowledged by competent parties to 
be one of the most important improvements ever hereto- 
fore made in the construction of steam-boilers. It is the 
invention of James W. Connery, foreman of the Boiler 
Department at the Baldwin Locomotive Works, Phila., 
and is known as Connery's Concave Calking. By this 
method the dangers to life and property induced by the 
old system of calking are entirely obviated, as even the 
uninitiated cannot dent or gall the plates with Connery's 
Patent Calking ; the importance of which will be appreci- 
ated by all steam users, more especially when it is known 
that it is impossible, for even the most skilful boiler- 
maker, to calk a boiler with the old-fashioned calking-tools 
without permanent injury to the plates. An illustration 
of which may be seen on page 465. The process of calk- 
ing is also so simplified by Connery's Concave Method as to 
give it, in point of economy, claims to universal adoption. 

* See page 389. 



468 HAND-BOOK OF LAND AKD MARINE ENGINES. 

STRENGTH OP THE STAYED AND FLAT SURFACES. 

The sheets that form the sides of fire-boxes are neces- 
sarily exposed to a vast pressure, and consequently some 
expedient has to be devised to prevent the metal at these 
parts from bulging out. 

Stay - bolts are generally placed at a distance of 4J 
inches from centre to centre all over the surface of fire- 
boxes, and thus the expansion or bulging of one side is 
prevented by the stifiness or rigidity of the other. 

Now, in an arrangement of this kind, it becomes neces- 
sary to pay considerable attention to the tensile strength 
of the stay-bolts employed for the above purpose, since 
the question of the ultimate strength of this part of the 
boiler is now transferred to them, it being impossible that 
the boiler-plates should give way unless the stay-bolts 
break in the first instance. 

Accordingly, all the experiments that have been made, 
by way of test, of the strength of stay - bolts, possess the 
greatest interest for the practical engineer. Mr. Fair- 
bairn^s experiments are particularly valuable. He con- 
structed two flat boxes, 22 inches square. The top and 
bottom plates of one were formed of J inch copper, and of 
the other | inch iron. There was a 2J inch water-space 
to each, with j| inch iron stays screwed into the plates and 
riveted on the ends. In the first box, the stays were placed 
five inches fro^n centre to centre, and the two boxes tested 
by hydraulic pressure. 

In the copper box, the sides commenced to bulge at 
450 pounds pressure to the square inch ; and at 810 pounds 
pressure to the square inch the box burst, by drawing the 
head of one of the stays through the copper plate. 

In the second box, the stays were placed at 4 inch 
centres ; the bulging commenced at 515 pounds pressure 



HAND-BOOK OF LAND AND MARINE ENGINES. 469 

to the square inch. The pressure was continually aug- 
mented up to 1600 pounds. The bulging between the 
rivets at that pressure was one-third of an inch ; but still 
no part of the iron gave way. At 1625 pounds pressure 
the box burst, and in precisely the same way as in the first 
experiment — one of the stays drawing through the iron 
plate, and stripping the thread in the plate. 

These experiments prove a number of facts of great 
value and importance to the engineer. In the first place, 
they show that, with regard to iron stay-bolts, their tensile 
strength is at least equal to the grip of the plate. 

The grip of the copper bolt is evidently less. As each 
stay, in the first case, bore the pressure on an area of 
5x5=25 square inches, and in the second, on an area of 
4x4=16 square inches, the total strains borne by each 
stay were, for the first 815x25=20,375 pounds on each 
stay; and for the second 1625x16=26,000 pounds on 
each stay. These strains were less, however, than the 
tensile strength of the stays, which would be about 28,000 
pounds. 

The properly stayed surfaces are the strongest part of 
boilers when kept in good repair. 

DEFINITIONS AS APPLIED TO BOILERS AND BOILER 
MATERIALS. 

Tensile strength is the absolute resistance which a 
body makes to being torn apart by two forces acting in 
opposite directions. 

Working Strength. — The term "working strength" 
implies a certain reduction made in the estimate of the 
strength of materials, so that, when the instrument or 
machine is put to use, it may be capable of resisting a 
greater strain than it is expected on the average to 
sustain. 
40 



470 HAND-BOOK OF LAND AND MARINE ENGINES. 

Safe Working Pressure, or Safe Load. — The 

working pressure of steam-boilers is generally taken as ^ 
of the bursting pressure, whatever that may be. 

Elasticity is that quality which enables a body or boiler 
to return to its original form after having been distorted 
or stretched by some extreme force. 

Internal Radius. — The internal radius is i of the di- 
ameter less the thickness of the iron. To find the internal 
radius of a boiler, take i of the external diameter and 
subtract the thickness of the iron. 

Longitudinal Seams. — The seams which are parallel 
to the length of a boiler are called the longitudinal 
seams. 

Curvilinear Seams. — The curvilinear seams of a boiler 
are those around the circumference. 

TABLE 

DEDUCTED FROM EXPERIMENTS ON IRON PLATES FOR STEAM- 
BOILERS, BY THE FRANKLIN INSTITUTE, PHILADELPHIA. 

Iron boiler-plate was found to increase in tenacity as its 
temperature was raised, until it reached a temperature of 
550"^ above the freezing-point, at which point its tenacity 
began to diminish. 

At 32° to 80° tenacity is 56,000 lbs. or one-seventh below its 

maximum. 

" 570° " " 66,000 " the maximum. 

" 720° " " 55,000 " the same nearly as at 30°. 

" 1050° " " 32,000 " nearly one-half the max- 

imum. 

'' 1240° " " 22,000 " nearly one-third the max- 

imum. 

" 1317° " " 9,000 " nearly one-seventh the 

maximum. 

It will be seen by the above table that if a boiler should 



HAin)-BOOK OF LAND AND MARINE ENGINES. 471 

become overheated, by the accumulation of scale on some 
of its parts or an insufficiency of water, the iron would 
soon become reduced to less than one-half its strength. 

TABLE 

SHOWING THE RESULT OP EXPERIMENTS MADE ON DIFFERENT 
BRANDS OF BOILER IRON AT THE STEVENS INSTITUTE OF 
TECHNOLOGY, HOBOKEN, N. J. 

Thirty-three experiments were made upon iron taken 
from the exploded steam-boiler of the ferry-boat Westfield. 
The following were the results : — 

Lbs. per 
sq. inch. 

Average breaking weight 41,653 

16 experiments made upon high grades of American boiler- 
plate. 

Average breaking weight 54,123 

15 experiments made upon high grades of American flange- 
iron. 

Average breaking weight 42,144 

6 experiments made upon English Bessemer steel. 

Average breaking weight 82,621 

5 experiments made upon English lowmoor boiler-plate. 

Average breaking weight 58,984 

6 experiments made upon samples of tank -iron from dif- 

ferent manufacturers. 

Average breaking weight. No. 1 43,831 

" " " No. 2 42,011 

" " " No. 3 41,249 

2 experiments made on iron taken from the exploded 
steam-boiler of the Red Jacket. 
Average breaking weight 49,000 

It will be noticed that the above experiments reveal a 
great variation in the strength of boiler-plates of different 
grades of iron, and furnish conclusive evidence that the 
tensile strength of boiler-iron ought to be taken at 50,000 
pounds to the square inch instead of 60,000. 



472 HAND-BOOK OF LAND AND MARINE ENGINES. 

FEED-WATER HEATERS, 

Inattention to the temperature of feed-water for boilers 
is entirely too common ; as the saving in fuel that may be 
effected by thoroughly heating the feed- water — by means 
of the exhaust steam in a properly constructed heater — 
would be immense, which will be seen from the following 
facts : 

A pound of feed-water entering a steam-boiler at a tem- 
perature of 50° Fah., and evaporating into steam of 60 
pounds pressure, requires as much heat as would raise 
1157 pounds of water 1 degree. A pound of feed- water 
raised from 50^ Fah. to 220^ Fah., requires 987 thermal 
units of heat ; which, if absorbed from exhaust-steam pass- 
ing through a heater, would be a saving of 15 per cent, in 
fuel. Feed- water, at a temperature of 200° Fah., entering 
a boiler, as compared in point of economy with feed-water 
at 50^, would effect a saving of over 13 per cent, in fuel ; 
and with a well-constructed heater there ought to be no 
trouble in raising the feed-water to a temperature of 212° 
Fah. 

If we take the normal temperature of the feed-water at 

60°, the temperature of the heated water at 212°, and the 

boiler pressure at 20 pounds, the total heat imparted to 

the steam in one case is 1192'5°— 60° = 1132-5°, and in 

the other case 1192-5°— 212° = 980-5°, the difference being 

152 
152°, or a saving of , = 13*4 per cent. 

Supposing the feed-water to enter the boiler at a tem- 
perature of 32° Fah., each pound of water will require 
about 1200 units of heat to convert it into steam, so that 
the boiler will evaporate between 61 and 7} pounds of 
water per pound of coal. The amount of heat required 
to convert a pound of water into steam varies with the 
pressure, as will be seen by the following table. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



473 



TABLE 

SHOWING THE UNITS OP HEAT REQUIRED TO CONVERT ONE POUND 
OF WATER, AT THE TEMPERATURE OF 32° FaHR., INTO STEAM 
AT DIFFERENT PRESSURES. 



Pressure of Steam 




Pressure of Steam 




in Pounds per 


Units of Heat. 


in Pounds per 


Units of Heat. 


sq. inch by Gauge. 




sq. inch by Gauge. 




1 


1,148 


110 


1,187 


10 


1,155 


120 


1,189 


20 


1,161 


130 


1,190 


30 


1,165 


140 


1,192 


40 


1,169 


150 


1,193 


50 


1,173 


160 


1,195 


60 


1,176 


170 


1,196 


70 


1,178 


180 


1,198 


80 


1,181 


190 


1,199 


90 


1,183 


200 


1,200 


100 


1,185 







If the feed-water has any other temperature, the heat 
necessary to convert it into steam can easily be computed. 
Suppose, for instance, that its temperature is 65°, and that 
it is to be converted into steam having a pressure of 80 
pounds per square inch. The difference between 65 and 
32 is 33 ; and subtracting this from 1181 (the number of 
units of heat required for feed-water having a temperature 
of 32°), the remainder, 1148, is the number of units for 
feed- water with the given temperature. 

Yet it must be understood that any design of heater 
that offers such resistance to the free escape of the exhaust 
steam as to neutralize the gain that would otherwise be 
obtained from its use, ought to be avoided, as the loss 
occasioned by back pressure on the exhaust in many 
instances overbalances that derived from the heating of 
the feed- water. 

It is a common practice on steamships to heat the feed- 
40* 



474 HAND-BOOK OF LAND AND MARINE ENGINES. 

water to 135° or 140° before sending it into the boiler. 
Where the jet condenser is used, this extra heat is derived 
from the blow-water ; but as this means of heating is not 
available with the surface condenser, it is generally derived 
from a water-jacket surrounding the smoke-stack, or a 
spiral pipe within the stack. But although any heat im- 
parted to the feed-water is a clear gain, yet the cost, com- 
plication, and danger of these arrangements generally 
overbalance the benefits derived from their use. 



STEAM-JACKETS. 

The steam in passing from the boiler to the cylinder 
sustains a loss by condensation, friction, etc., more particu- 
larly if the pressure be high. The conducting properties 
of the metal rob the steam of its heat in proportion to the 
difference of the temperature. The office of the steam- 
jacket is to prevent this waste by keeping the walls of 
the cylinder at a constant temperature, so as to prevent 
the pressure of water in the cylinder and the resulting 
inconvenience. 

The benefit to be derived from the use of the steam- 
jacket has not heretofore been fully understood, as an idea 
very generally prevailed among engineei's, that waste by 
radiation was the only loss incident to the cooling of a 
steam-cylinder, and that this loss would be as great in the 
jacket as in the cylinder ; whereas the loss is by no means 
measurable by the loss from the radiation, but is a much 
larger loss, and arises from the fact of the inner surface 
of the cylinder being cooled and heated by the steam at 
every stroke of the engine. 

By comparing the diagrams obtained from cylinders 
without jackets with the theoretical curve, the loss has 
been found to amount in different cases from 10 to 15 per 



HAND-BOOK OP LAND AKD MARINE ENGINES. 475 

cent. This loss is caused by the circumstance that the 
mass of the cylinder must remain at the average tempera- 
ture intermediate between the highest and the lowest 
temperatures of the steam, so that when high-pressure 
steam, which also has a high temperature, enters the 
cylinder, a considerable quantity of it is at once condensed, 
owing to the abstraction of heat by the metal, and also to 
the transformation of a part of the heat into mechanical 
power. Hence, the necessity of clothing high-pressure 
cylinders and pipes with felt or other non-conducting 
substance to prevent the absorption of the caloric. 

LOSS OP PRESSURE IN CYLINDERS INDUCED BY 
LONG STEAM-PIPES. 

It is well known that the initial pressure in steam-cylin- 
ders seldom equals the boiler pressure. This loss of press- 
ure is usually attributed to the frictional resistance of the 
steam-pipe and condensation within the latter. There is 
reason to believe, however, that although such a deduction 
is consistent with facts in many cases, it is by no means 
always so. It is of course quite possible to make a steam - 
pipe so small, and so full of bends and sharp turns, that 
it will cause considerable resistance, and consequently loss 
of power. But it would perhaps be found on investigation, 
in all cases where a considerable loss of power takes place, 
that the velocity of the steam is over 100 feet per second. 

The only inducement to make steam-pipes too small 
is the first cost ; but the wisdom of such economy is ex- 
tremely doubtful, as, when steam-pipes are large enough, 
very little loss of pressure takes place, even though the 
pipe be two or three hundred yards long, so far as fric- 
tional resistance can affect the question. 

There is only one other cause of loss of pressure, and that 



476 HAND-BOOK OF LAND AND MARINE ENGINES. 

is condensation. The remedy for this is obvious, as, if the 
steam-pipe be protected, the loss of pressure will be very- 
slight. One of the best means to accomplish this is to lay 
the steam-pipe under ground, in large wooden troughs, — 
water-proof, if the ground be damp, — the troughs to be 
filled with dried saw-dust or fine dry sand. If this arrange- 
ment be inadmissible, then the pipes should be covered 
with felt, or some one or other of the various compositions 
in use for that purpose. The loss by condensation may 
in this manner be reduced to one or two per cent, of the 
whole quantity of steam used by the engine. 

PRIMING IN STEAM-CYLINDERS. 

Steam almost invariably contains more or less fine 
particles of water in its ordinary form ; and, although every 
efibrt is made in steam-engineering to procure dry steam, 
or steam as free as possible from such particles, these 
eflforts are not always successful, perhaps for the reason 
that the precise nature of this action is not understood, as 
it is of course not subject to inspection under such circum- 
stances as occur in practice. 

There are some reasons for supposing that the water, 
under the influence of some unknown law, ascends the side 
of the boiler in a thin sheet, and thus flows out with the 
steam from the steam-pipe ; but there are stronger reasons 
for supposing it to rise in the form of thick spray mingled 
intimately with the vapor. This theory derives much 
support from the fact that simple deflecting plates of iron, 
placed in boilers in such a manner as to deflect the water 
and throw it against the sides of the boiler, to descend by 
its own gravity, have, in numerous instances, almost or en- 
tirely remedied this evil. 

Some boilers are far more liable to work water than 



HAND-BOOK OF LAND AND MARINE ENGINES. ,477 

others ; and the reason cannot always be satisfactorily- 
assigned for this difference ; but in general a large area 
of water surface in the boiler, or, in other .words, a liberal 
provision for the escape or disengagement of the steam 
from the water, so that it does not rise therefrom in any 
considerable velocity, tends very greatly to prevent prim- 
ing. The steam-domes added on the top of many high- 
pressure boilers, and the steam chimney on low-pressure 
boilers, are both intended for the same purpose, to take 
the steam at a considerable elevation, so as to avoid the 
commotion of the water as far as possible. 

The steam chimney, however, in the last-named ex- 
ample, contains the heated smoke stack or uptake, which 
tends very considerably to dry the steam by evaporating 
all the particles of water which come in contact with it. 
But with all precautions, engines are always liable to 
receive a greater or less quantity of water, to which may 
be added an allowance for the quantities, sometimes very 
considerable, which are condensed by contact with the 
cold metal of the cylinder in commencing to work. 

As water is incompressible, except to a very small 
degree, and as the piston at each stroke comes into almost 
absolute contact with all parts of the cylinder end, it 
follows that a quantity of water sufficient to more than 
fill the small space remaining before the piston at the end 
of the stroke, must necessarily compel either a stoppage of 
the engine or a fracture of some portion of the machinery, 
unless means are provided for its escape. 

OILS AND OILING. 

Oils are divisible into two distinct classes — fat or fixed 
oils, and the essential or volatile oils. The former are 
usually bland to the taste ; the latter, hot and pungent. 



478 HAND-BOOK OF LAND AND MARINE ENGINES 

Whether of animal or vegetable origin, they possess the 
same ultimate constituents — carbon, hydrogen, and gen- 
erally oxygen, and in nearly the same proportions. The 
fat oils are mixtures of three substances of similar proper- 
ties ; two of them at ordinary temperature are solid, called 
stearine and margarine, and the third is a fluid called 
oleine. The proportion of the latter gives softness and 
fluidity to the compound. 

In close vessels, oils may be preserved fresh for a long 
time; but in contact with air they undergo progressive 
changes. Oils which thicken, and eventually dry into a 
transparent, flexible substance, are said to be drying or 
siccative, and used for preparations for varnishes and 
painters' colors. Other oils do not become dry, though 
they turn thick, become less combustible, and assume an 
ofiensive smell ; they are then called rancid, and exhibit 
an acid reaction, which may be removed in a great meas- 
ure by boiling the oil along with water and a little com- 
mon magnesia for a quarter of an hour, or until it has lost 
the property of reddening litmus. 

Now, as the cost of oil, like that of fuel, is among the 
heaviest items of expenditure incident to the use of the 
steam-engine, its reckless waste can only be attributed to 
ignorance ; as no one, however careless, would hardly be 
guilty of such criminal waste in the use of oil as is often 
manifest, especially when any intelligent person can learn 
by a very short experience the proper quantity needed for 
any bearing, and that the amount of oil which a bearing 
will carry is limited, as, after the surface has been cov- 
ered, every drop of oil poured on the journal or rubbing 
surface, is thrown off* and wasted. The common practice 
of going about with a squirt-can and spirting oil at the 
bearings of a steam-engine, not into them, cannot be too 
severely censured. 



HAND-BOOK OF LAXD AND MARINE ENGINES. 479 

The frequency with which oil is to be supplied into the 
cylinder is also a very important point, for the same rule 
applies here as to the bearing, as all that is not essential 
to the work is thrown away by the engine or carried out 
with the exhaust. It not unfrequently happens that e:f- 
haust - pipes have their areas greatly diminished in con- 
sequence of becoming coated with the tallow so needlessly 
poured into the cylinders. 

On the question of lubricating steam - cylinders, like 
many others connected with steam-engineering, a differ- 
ence of opinion exists among engineers, for while some 
claim that a lubricant is not at all needed, others stoutly 
contend that it is absolutely necessary. And in defence 
of the former theory, numerous instances might be cited 
of steam-engines that have been running for years with- 
out a drop of oil in their cylinders or steam-chests ; but it 
must be borne in mind that these are exceptional cases, 
and may be due to the state of the steam, the construction 
of the engine, and nature of the metals in contact. By 
the state of the steam is meant whether it is saturated or 
superheated. Therefore, because one engine here and 
there runs without oil in the parts mentioned, it does not 
follow, as a rule, that no valve-seat or piston requires to 
lubricated. 

It may be well to observe here that the waste of grease 
incurred by its lavished use is not the only loss occasioned, 
but the injury which the cylinder, valve-faces, and pack- 
ing sustain from the too free use of tallow renders it highly 
detrimental to the durability of the parts mentioned. In 
the rendering of rough fats, such as are used for greasing 
cylinders and pistons, sulphuric acid is freely used. The 
quantity of the acid used amounts to, at the least, 12 per 
centum of the weight of fat, and it combines at once with 
the whole of the fatty matter; a portion of the acid is 



480 



HAND-BOOK OF LAND AND MARINE ENGINES. 



removed by washing the grease in water at a high tem- 
perature ; but a certain part remains behind and becomes 
a constituent of the rendered mass. 

This acid is set free when introduced to the steam-cyl- 
inder by the heat therein, and, though necessarily small 
in quantity to the proportion of grease introduced, at once 
exerts its evil influence, and slowly but surely destroys 
the metal. The iron is eaten up, and the carbon alone 
remains. Animal fats are themselves acids, chemically 
speaking; but these are not specially injurious to iron. 
The best way to avoid the trouble before-mentioned is to 
use good refined tallow ; but as it is somewhat difiicult to 
procure such an article nowadays^ lard-oil should be used, 
as it is undoubtedly the next best lubricant for the steam- 
cylinders. 

TABLE 

OF COEFFICIENTS OF FRICTIONS BETWEEN PLANE SURFACES. 



Sliding 
surface. 



Cast-iron. 



Cast-iron. 



Wrought- 
iron. 



Bronze. 



Surface 
at rest. 



Wrought- 
iron. 



Cast-iron. 



Bronze. 



Wrought- 
iron. 



State of the Surfaces. 



r Fibres of both 
-j surfaces paral- 
( lei to motion. . i 



f Fibres parallel 
\ to motion. ^ 



Lubri- 
cated 
with 



Surfaces unctuous. 
Without lubric. 
Surfaces unctuous. 

tallow. 

lard. 

olive-oil. 

lard and 

pFbago. 
Without lubric. 
Surfaces unctuous. 
Lubri- r tallow, 
cated -j lard, 
with ( olive-oil. 
Without lubric. 
Surfaces unctuous. 

! tallow, 
lard and 
pPbago. 
olive-oil. 



Lubri- 
cated 
with 



Coeffi 
cientof 
Fric- 
tion. 



0.143 
0.152 
0.144 
0.100 
0.070 
0.064 

0.055 
0.072 
0.060 
0.103 
0.075 
0.078 
0.161 
0.166 
0.081 

0.089 
0.072 



HAND-BOOK OF LAND AND MARINE ENGINES. 



481 



TABLE — {Continued) 
OF COEFFICIENTS OF FRICTIONS BETWEEN PLANE SURFACES. 



Sliding 
surface. 



Cast-iron. 



Bronze. 



Bronze. 



Brass. 



Steel. 



Surface 
at rest. 



Steel. 
Steel. 



Bronze. 



Cast-iron. 



Bronze. 



Cast-iron, 



Cast-iron 



Wrought- 

iron. 
Bronze. 



State of the Surfaces. 



Coeffi- 
cientof 
Fric- 
tion. 





41 



Fibres of 

iron parallel 

to motion. 



2F 



Without lubric. 
Surfaces unctuous. 
Lubri- r tallow, 
cated -j lard, 
with i olive-oil. 
Without lubric. 
Surfaces unctuous. 

Jfted" Vf''^-., 
with jolive-oil. 

Without lubric. 
Surfaces unctuous. 
Lubricated with 

olive-oil. 
Without lubric. 
Surfaces unctuous. 
Lubri- r tallow., 
cated -j lard, 
with ( olive-oil. 
Without lubric. 
Lubri- I tallow, 
cated \ lard, 
with ( olive-oil. 

with ji^--^; 

Without lubric. 
tallow. 



Lubri- 
cated 
with 



olive-oil. 
lard and 
pl'bago. 



0.147 
0.132 
0.103 
0.075 
0.078 
0.217 
0.107 

0.086 
0.077 

0.201 
0.134 

0.058 

0.189 
0.115 
0.072 
0.068 
0.066 
0.202 
0.105 
0.081 
0.079 

0.093 
0.076 

0.152 
0.056 
0.053 

0.076 



482 HAND-BOOK OF LAND AND MARINE ENGINES. 

GRATE-BARS. 




The grate-bap has not heretofore received that considera- 
tion from engineers and steam users that its importance, 
in an economical point of view, so eminently deserves. 

Perfect combustion is the starting-point in the genera- 
tion of steam ; the conversion of coal and air into heat 
must be the first process, and the second is to apply that 
heat with full effect to the boiler. 

The oxygen of the air is the only supporter of combus- 
tion, and the rate of combustion produced, and the amount 
of heat generated in the furnace, depend on the quantity 
of air supplied, and the quantity of air admitted depends 
on the size of the opening through which it passes. 

Then, as a matter of course, the grate-bars that offer the 
least obstruction to the air passing through them, and 
afford the largest area for the air combined with an equal 
distribution of the same, must be the most perfect for the 
purposes of combustion. 

The destruction of grate-bars may be traced to three 
causes — breaking, warping, and burning out ; consequently, 
grate-bars, to be durable and efficient, should have a narrow 
surface exposed to the fire, and the spaces for admitting 
the air should be numerous and well distributed. 

The metal constituting the bar should be distributed in 
the best possible manner, to relieve the grate from all 
undue strain arising from unequal expansion and con- 
traction ; there should also be considerable depth, in order 
that the lower edges may keep cool and prevent the pos- 
sibility of warping or twisting. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



483 



Grate-bars of good design and proportions are fre- 
quently ruined by being exposed to a white heat whenever 
a fresh lire is started, when, by distributing a thin layer of 
fresh coal over their surface before the shavings and wood 
are applied, they may be preserved intact for years. 

CHIMNEYS. 

The object of a chimney is to 

convey away the smoke and to 
produce a draught — that is, a cur- 
rent of fresh, dry air through the 
coals on the grate ; this draught 
is produced by the diflference in 
the specific gravity of the air in- 
side and outside of the chimney. 
If the quality of the gases inside 
and outside were always the same, 
formulae could be established for 
the size of chimneys with a con- 
siderable degree of accuracy. 

The gases inside of a chimney 
are generally composed of atmos- 
pheric air, free nitrogen, carbonic 
acid, carbonic oxide, steam, free 
hydrogen, free carbon, sulphur- 
ous acid, and other elements. If 
the relative amount of these gases 
and their temperature were al- 
ways the same, there would not 
be much difficulty in determining 
the proportions ; but as these con- 
ditions are continually changing, as well by the gradual 
consumption of the coal on the grate, as by the manage- 
ment of the party in charge, it is almost impossible to 
arrive at any exact or definite conclusion. The air out- 



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1 








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1 




















1 




















1 






































































































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1 1 




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484 



HAND-BOOK OF LAND AND MARINE ENGINES. 



side the chimney is also continually undergoing changes, 
produced by moisture, temperature, density, etc. 

Fop stationary and marine boilers the chimneys are 
generally of a uniform height, arising from the nature of 
the structures with which they are connected, and hence 
the approximate amount of combustion on a square foot 
of grate surface, and the resulting evaporation of water per 
hour, are pretty well known from practical observations; 
but still, experiments are greatly needed to determine the 
proper proportions of chimneys for different kinds of fuel. 

For marine boilers the general rule is to allow 14 
square inches area of chimney for each nominal horse- 
power. For stationary boilers, the area of the chimney 
should be one-fifth greater than the combined area of all 
the flues or tubes. 

Rule jor finding the Required Area of Chimney for any 
Boiler, — Multiply the nominal horse-power of the boiler 
by 112, and divide the product by the square root of the 
height of the chimney in feet. The quotient will be the 
required area in square inches. 

TABLE 

SHOWING THE PROPER DIAMETER AND HEIGHT OF CHIMNEY FOR 
ANY KIND OF FUEL. 



Nominal Horse-power 


Height of Chimney 


Inside Diameter at 


of Boiler. 


in Feet. 


Top. 


10 


60 


1 foot 2 inches. 


12 


75 


1 " 2 " 


16 


90 


1 " 4 " 


20 


99 


1 " 5 " 


30 


105 


1 " 9 " 


50 


' 120 


2 feet 2 " 


70 


120 


2 '' 6 " 


90 


120 


2 " 10 " 


120 


135 


3 " 2 " 


160 


150 


3 " 7 ^^ 


200 


165 


3 " 11 '' 


250 


180 


4 « 4 " 



flAND-BOOK OF LAND AND MARINE ENGINES. 485 

SMOKE. 

Notwithstanding the number of smoke-burning furnaces 
which have at different times been introduced, it cannot 
be said that any plan has yet been contrived which so far 
satisfies the conditions of the problem as to command gen- 
eral recognition of its suitability, or to lead to its general 
adoption. 

These plans operate either on the principle of admitting 
air above the fuel to burn the smoke, — which has the radi- 
cal defect that the production of smoke in ordinary 
furnaces is variable, whereas the admission of air is con- 
stant, so that either too much or too little will generally 
enter, — or on the principle of passing the smoke over the 
incandescent fuel, or through red-hot pipes or fire-brick 
passages, which, though it will diminish the smoke, will 
rarely wholly prevent it. 

A great many experiments would be tried, but a lack 
of knowledge of the principles involved would, in a 
majority of cases, render success impossible, as not one en- 
gineer in a hundred, if required to consume smoke, so far 
as his own furnace is concerned, would have any clear idea 
how to proceed to do it. 

From how many smoke-stacks throughout the land can 
great volumes of smoke, as black as midnight, be seen, at 
almost all times, rolling upward, carrying with them the 
most valuable proportions of the fuel ! Each one of 
these advertises a great waste, which is generally produced 
by the boilers being too small. 

With boilers of suitable proportions, grate surface ade- 
quate to the quantity of fuel to be consumed, and furnaces 
properly constructed, this waste occasioned by smoke 
would not occur; as the loss and inconvenience caused 
by smoke are generally aggravated by a false economy in 
41^ 



486 HAND-BOOK OF LAND AND MARINE ENGINES. 

the first cost of boilers, a want of skill in their setting, 
and ignorance and carelessness in their management. 

But it must be understood that all that comes out of 
the chimney is not smoke, by any means. Bituminous 
coal contains from five to six per cent, of hydrogen, which 
unites with the oxygen necessary to combustion, and makes 
water. A ton of bituminous coal will make nearly one- 
third of a ton of water, in the form of steam. 

That this steam is black does not necessarily indicate 
the presence of much carbon, as a grain of soot, if dis- 
tributed evenly in fine particles through a cubic foot of 
steam, would color it blacker than the ace of spades. 

Now it requires no argument to show that this steam 
cannot be burned. It may be condensed by being made 
to pass through tubes kept at a low temperature, though 
a draught could only be maintained artificially under 
these conditions, but it cannot be consumed. If it were 
possible to separate the carbon atoms from the vapor in 
which they are held suspended, they could be burned ; but 
such a separation could not be effected, and if it could, 
the amount of fuel saved would be very small. 

Since the days of Watt, the consumption of smoke has 
attracted the attention of scientists, inventors, and en- 
gineers, but, so far, without any very practical results, as 
the methods that offered the most plausible solution of the 
problem involved in the burning of smoke have invariably 
failed to produce such results as would warrant their 
adoption into general use. A uniform supply of fuel to 
the furnace, and the introduction of air above the fire, 
were advocated as furnishing a remedy for the loss occa- 
sioned by smoke ; but the former was, in most cases, found 
impracticable and inconvenient on account of the varying 
circumstances involved in the management of furnaces ; 
whilst the latter was frequently productive of more waste 



HAin)-BOOK OF LAND AND MARINE ENGINES. 487 

than that occasioned by smoke, in consequence of the 
current of cool air above the fire being constant, and the 
quantity of fuel on the grate and the temperature of the 
furnace seldom so. 

When smoke is once formed, it cannot be burned by any 
known device. 

The consumption of smoke would be a great benefit, 
not more so in point of economy than in comfort and 
convenience. 

MENSURATION OF THE CIRCLE, CYLINDER, St>HERE, 

ETC. 

1. The circle contains a greater area than any other 
plain figure bounded by an equal perimeter or outline. 

2. The areas of circles are to each other as the squares 
of their diameters. 

3. The diameter of a circle being 1, its circumference 
equals 3-1416. 

4. The diameter of a circle is equal to '31831 of its cir- 
cumference. 

5. The square of the diameter of a circle being 1, its 
area equals '7854. 

6. The square root of the area of a circle multiplied by 
1*12837 equals its diameter. 

7. The diameter of a circle multiplied by '8862, or the 
circumference multiplied by '2821, equals the side of a 
square of equal area. 

8. The sum of the squares of half the chord and versed 
sine divided by the versed sine, the quotient equals the 
diameter of corresponding circle. 

9. The chord of the whole arc of a circle taken from 
eight times tlie chord of half the arc, one-third of the 
remainder equals the length of the arc ; or, 

10. The number of degrees contained in the arc of a 



488 HAND-BOOK OF EAND AND MARINE ENGINES. 

circle, multiplied by the diameter of the circle and by 
•008727, the product equals the length of the arc in equal 
terms of unity. 

11. The length of the arc of a sector of a circle 
multiplied by its radius, equals twice the area of the 
sector. 

12. The area of the segment of a circle equals the area 
of the sector, minus the area of a triangle whose vertex is 
the centre, and whose base equals the chord of the seg- 
ment; or, 

13. The area of a segment may be obtained by dividing 
the height of the segment by the diameter of the circle, 
and multiplying the corresponding tabular area by the 
square of the diameter. 

14. The sum of the diameters of two concentric circles 
multiplied by their difference, and by '7854, equals the 
area of the ring or space between them. 

15. The sum of the thickness and internal diameter of 
a cylindric ring multiplied by the square of its thickness, 
and by 2*4674, equals its solidity. 

16. The circumference of a cylinder multiplied by its 
length or height equals its convex surface. 

17. The area of the end of a cylinder multiplied by its 
depth equals its cubical capacity. 

18. The square of the diameter of a cylinder multiplied 
by its length, and divided by any other required length, 
the square root of the quotient equals the diameter of the 
other cylinder of equal contents or capacity. 

19. The square of the diameter of a sphere multiplied 
by 3*1416 equals its convex surface. 

20. 'the cube of the diameter of a sphere multiplied by 
'5238 equals its solid contents. 

21. The height of any spherical segment or zone multi- 
plied by the diameter of the sphere of which it is a part, 



HAND-BOOK OF LAND AND MARINE ENGINES. 489 

and by 31416, equals the area or convex surface of the 
segment; or, 

22. The height of the segment multiplied by the circum- 
ference of the sphere of which it is a part, equals the 
area. 

23. The solidity of any spherical segment is equal to 
three times the square of the radius of its base, plus the 
square of its height, and multiplied by its height and by 
•5236. 

24. The solidity of a spherical zone equals the sum of 
the squares of the radii of its two ends, and one-third the 
square of its height multiplied by the height and by 
1-5708. 

25. The capacity of a cylinder 1 foot in diameter 
and 1 foot in length equals 5*875 of a United States 
gallon. 

26. The capacity of a cylinder 1 inch in diameter and 
1 inch in length equals -0034 of a United States gallon. 

27. The capacity of a sphere 1 foot in diameter equals 
3*9156 United States gallons. 

28. The capacity of a sphere 1 inch in diameter equals 
•002165 of a United States gallon; hence, 

29. The capacity of any other cylinder in United States 
gallons is obtained by multiplying the square of its 
diameter by its length, or the capacity of any other 
sphere by the cube of its diameter, and by the number of 
United States gallons contained as above in the unity of 
its measurement. ' 

Rule for finding the Area of a Circle, — Multiply the 
circumference by one-quarter of the diameter ; or, multi- 
ply the square of the diameter by -7854 ; or, multiply the 
square of the circumference by '07958 ; or, multiply half 
the circumference by half the diameter ; or, multiply the 
square of half the diameter by 3'1416. 



490 HAND-BOOK OF LAND AND MARINE ENGINES. 



CENTRAL AND MECHANICAL FORCES AND DEFINI- 
TIONS. 

Acceleration. — Acceleration is the increase of velocity 
in a moving body caused by the continued action of the 
motive force. When bodies in motion pass through equal 
spaces in equal time, or, in other words, when the velocity 
of the body is the same during the period that the body is 
in motion, it is termed uniform motion, of which we have 
a familiar instance in the motion of the hands of a clock 
over the face of it ; but a more correct illustmtion is the 
revolution of the earth on its axis. In the case of a body 
moving through unequal spaces in equal times, or with a 
varying velocity, if the velocity increase with the duration 
of the motion, it is termed accelerated motion ; but if it 
decrease with the duration of the motion, it is termed 
retarded motion. 

Affinity. — Affinity is a term used in chemistry to denote 
that kind of attraction by which the particles of diiferent 
bodies unite, and form a compound possessing properties 
distinct from any of the substances which com{)ose it. 
Thus, when an acid and alkali combine, a new substance 
is formed called a salt, perfectly different in its chemical 
properties from either an acid or an alkali ; and the ten- 
dency which these have to unite is said to be in consequence 
of affinity. 

Angle. — If two lines drawn on a pjane surface are so 
situated that they meet in a point, or would do so, if long 
enough, they form an opening, which is called an angle. 
The one line meeting another makes the angle on both 
sides equal to each other \ then these angles are each called 
a right angle, and in this case the one line is said to be 
perpendicular to the other, or, in the language of mechanics, 
the one line is said to be square with the other ; and if 



HAND-BOOK OF LAND AND MARINE ENGINES. 491 

the one line be horizontal, the perpendicular is said to be 
plumb to it. The arc which measures a right angle is the 
quarter of the whole circumference, or is a quadrant, and 
contains 90 degrees ; any angle measured by an arc less 
than this is acute (sharp), and if by an arc greater than 
a quadrant, obtuse (blunt). 

Axle. — An axle is a shaft supporting a wheel ; the 
wheel may turn on the axle, or be fastened to it, and 
the axle turn on bearings. Axles are viewed as having 
certain relations to girders in principle. Girders gener- 
ally have their two ends resting on two points of support, 
and the load is either located at fixed distances from the 
props, or dispersed over the whole surface of the axle ; the 
wheels may be considered the props and the journals the 
loaded parts. It is found that the inclined surface of the 
wheel-tire given by coning ranges from 1 to 12 to 1 to 
20 ; and, as a matter of course, the direct tendency of the 
wheel under a load is to descend that incline, so that every 
vertical blow which the wheels may receive is compounded 
of two forces, viz., the one to crush the wheels in the 
direction of their vertical plane, and the other to move 
the lower parts of the wheels together. It will be seen that 
these two forces have a direct tendency to bend the axle 
somewhere between the wheels. 

Capillary Attraction. — Capillary attraction is the 
property observable in small tubes and porous substances, 
such as sponge, lamp-wicking, thread, etc., of raising oil, 
water, or other fluids above their natural level. Hence 
the application of this principle is applied for obtaining a 
continuous supply of lubricating fluids between rubbing 
and revolving surfaces in motion, by means of a siphon 
constructed of wickings, worsted, or some other substance, 
one end of which is immersed in oil, and the other in- 
serted in the tube through which the fluid is to be con- 
ducted. 



492 HAND-BOOK OF LAND AND MARINE ENGINES. 

Centre of Gravity. — The forces with which all bodies 
tend to fall to the earth may be considered parallel ; hence 
every body may be considered as acted on by a system of 
parallel forces, whose resultant may be found, and these 
forces, in all positions of the body act on the same points 
in the same vertical direction. There is, therefore, in every 
body a point through which the resultant always passes, 
in whatever position it is placed. This point is called the 
centre of gravity of the body. The centre of gravity of a 
uniform cylinder or prism is in its axis, and at the middle 
of its length ; of a right cone or pyramid it is also in the 
axis, but at one-fourth of the height from the base. 

Dynamics. — Dynamics is that branch of mechanics 
which treats of forces in motion producing power and 
work. It comprehends the action of all kinds of machin- 
ery, manual and animal labor, in the transformation of 
physical work. 

Energy, — This term is used to denote work, but the 
sense of it conveys an idea of a different virtue, namely, 
that of activity or vigor, which is power. We say that a 
man has a great deal of energy when he can accomplish 
much work in a short time, which is virtue of power ; but 
if he accomplishes the same quantity of work in a much 
longer time, we do not give him credit for much energy. 
The term energy, if employed at all, ought to be applied 
to power alone ; but as we have the expressive term power 
for that function, it is better to dispense with the term 
energy in dynamics. 

Force. — Force is the cause of motion or change of 
motion in material bodies. Every change of motion, viz., 
every change in the velocity of a body, must be regarded 
as the effect of a force. On the other hand, rest, or the 
invariability of the state of motion of a body, must not 
be attributed to the absence of forces, for opposite forces 



HAND-BOOK OF LAND AND MARINE ENGINES. 493 

destroy each other and produce no effect. The gravity 
with which a body falls to the ground still acts, though 
the body rests ; but this action is counteracted by the 
solidity of the material upon which it reposes. 

Forces that are balanced so as to produce rest are 
called statical forces, or pressures, to distinguish them 
from moving, deflecting, accelerating, or retarding forces ; 
i, e,, such as are producing motion, or a change in the 
direction or velocity of motion. This distinction is wholly 
artificial, for the same force may act in any of these modes ; 
it may sometimes be a statical and sometimes an acceler- 
ating force. 

Force is any action which can be expressed simply by 
weight, and is distinguished by a great variety of terms, 
such as attraction, repulsion, gravity, pressure, tension, 
compression, cohesion, adhesion, resistance, inertia, strain, 
stress, strength, thrust, burden, load, squeeze, pull, push, 
pinch, punch, etc., all of which can be measured or ex- 
pressed by weight without regard to motion, time, power, 
or work. 

Focus. — Focus in geometry is that point in the trans- 
verse axis of a conic section at which the double ordinate 
is equal to the perimeter, or to a third proportional to the 
transverse and conjugate axis. 

Friction. — Friction is the resistance occasioned to the 
motion of a body when pressed upon the surface of 
another body which does not partake of its motion. 
Under these circumstances, the surfaces in contact have a 
certain tendency to adhere. Not being perfectly smooth, 
the imperceptible asperities which may be supposed to 
exist on all surfaces, however highly polished, become to 
some extent interlocked, and, in consequence, a certain 
amount of force is requisite to overcome Xhe mutual resist- 
ance to motion of the two surfaces and to maintain the 
42 



494 HAND-BOOK OF LAND AXD MARINE ENGINES. 

sliding motion even when it has been produced. By in- 
creasing the pressure, the resistance to motion is increased 
also ; and on the other hand, by rendering the surfaces 
more smooth and by lubrication, its amount is greatly 
diminished, but can never be entirely annulled. 

Friction cannot be strictly called a force, unless that 
term be taken in a negative sense. The tendency of force, 
in the rigid meaning of the word, is to produce motion ; 
whereas the tendency of friction is to destroy motion. 

Friction Rollers. — The obstruction which a cylinder 
meets in rolling along a smooth plane is quite distinct 
in its character, and far inferior in its amount to that 
which is produced by the friction of the same cylinder 
drawn lengthwise along a plane. For example, in the 
case of wood rolling on wood, the resistance is to the press- 
ure, if the cylinder be small, as 16 or 18 to 1000, and if the 
cylinder be large, this may be reduced to 6 to 1000. The 
friction from sliding, in the same cases, would be to the 
pressure as 2 to 10 or 3 to 10, according to the nature of 
the wood. Hence, by causing one body to roll on another, 
the resistance is diminished from 12 to 20 times. It is 
therefore a principle, in the composition of machines, that 
attrition should be avoided as much as possible, and 
rolling motions substituted whenever circumstances admit. 

Gravity and Gravitation. — These terms are often used 
synonymously to denote the mutual tendency which all 
bodies in nature have to approach each other. 

Gravity, Speoifio. — The specific gravity of a body is 
the ratio of its w^eight to an equal volume of some other 
body assumed as a conventional standard. The standard 
usually adopted for solids and liquids is rain or distilled 
water at a common temperature. 

In bodies of equal magnitudes, the specific gravities are 
directly as the weights or as their densities. In bodies of 



HAND-BOOK OF LAND AND MARINE ENGINES. 495 

the same specific gravities, the weights will be as the mag- 
nitudes. In bodies of equal weights the specific gravities 
are inversely as the magnitudes. The weights of different 
bodies are to each other in the compound ratio of their 
magnitudes and specific gravities. Hence, it is obvious 
that of the magnitude weight and specific gravity of a 
body, any two of these being given, the third may be 
found. 

A body immersed in a fluid will sink if its specific 
gravity be greater than that of the fluid ; if it be less, the 
body will rise to the top, and be only partly immerged ; 
and if the specific gravity of the body and fluid be equal, 
it will remain at rest in any part of the fluid in which it 
may be placed. When a body is heavier than a fluid, it 
loses as much of its weight when immersed as is equal 
to a quantity of the fluid of the same bulk or magnitude. 

If the specific gravity of the fluid be greater than that 
of the body, then the quantity of fluid displaced by the 
part immerged is equal to the weight of the whole body. 
And hence, as the specific gravity of the fluid is to that 
of the body, so is the whole magnitude of the body to the 
part immerged. The specific gravities of equal solids are 
as their parts immerged in the same fluid. 

Gyration, the Centre of. —The centre of gyration is 
that point in which, if all the matter contained in a revolv- 
ing system were collected, the same angular velocity will 
be generated in the same time by a given force acting at 
any place as would be generated by the same force acting 
similarly in the body or system itself. The distance of 
the centre of gyration from the point of suspension or the 
axis of motion, is a mean proportional between the dis- 
tances of the centres of oscillation and gravity from the 
same point or axle. 

Hopse-power, or Power of a Horse.— The power of a 



496 HAIsTD-BOOK OF LAND AND MARINE ENGINES. 

horse when applied to draw loads, as well as when made 
the standard of comparison for determining the value of 
other powers, has been variously stated. The relative 
strength of men and horses depends of course upon the 
manner in which their strength is applied. Thus, the 
worst way of applying the strength of a horse is to make 
him carry a weight up a steep hill, while the organization 
of the man fits him very well for that kind of labor. 
Three men climbing up a steep hill, each one having 100 
pounds on his shoulder, will proceed faster than most 
horses with 300 pounds. 

Hydpodynamics. — Hydrodynamics is that branch of 
general mechanics which treats of the equilibrium and 
motion of fluids. The terms hydrostatics and hydrodyn- 
amics have corresponding signification to the statics and 
dynamics in the mechanics of solid bodies, viz., hydro- 
statics is that division of the science which treats of the 
equilibrium of fluids, and hydrodynamics that which 
relates to their forces and motion. It is, however, very 
usual to include the whole doctrine of the mechanics of 
fluids under the general term of hydrodynamics, and to 
denote the divisions relative to their equilibrium and 
motion by the terms hydrostatics and hydraulics. 

Hyperbola, — A plane figure formed by cutting a sec- 
tion from a cone by a plane parallel to its axis, or to any 
plane within the cone, which passes through the cone's 
vertex. The curve of the hyperbola is such that the 
difference between the distances of any point in it from 
two given points is always equal to a given right line. 

If the vertexes of two cones meet each ether so that 
their axes form one continuous straight line, and the plane 
of the hyperbola cut from one of the cones be continued, 
it will cut the other cone, and form what is called the op- 
posite hyperbola, equal and similar to the former, and the 



HAND-BOOK OF LAND AND MARINE ENGINES. 497 

distance between the vertexes of the two hyperbolas is 
called the major axis, or transverse diameter. If the dis- 
tance between a certain point within the hyperbola, called 
the focus, and any point in the curve be subtracted from 
the distance of said point in the curve from the focus of 
the opposite hyperbola, the remainder will always be equal 
to a given quantity, that is, to the major axis ; and the 
distance of either focus from the centre of the major axis 
is called the eccentricity. The line passing through the 
centre, perpendicular to the major axis, and having the 
distance of its extremities from those of the axis equal to 
the eccentricity, is called the minor axis, or conjugate di- 
ameter. An ordinate to the major axis, a double ordinate, 
and an absciss mean the same as the corresponding lines 
in the parabola. 

Impact.— The single instantaneous blow or stroke com- 
municated from one body in motion to another either in 
motion or at rest. 

Impenetrability. — In physics, one of the essential prop- 
erties of matter, or body. It is a property inferred from 
invariable experience, and resting on this incontrovertible 
fact, that no two bodies can occupy the same portion of 
space in th© same instant of time. 

Impenetrability, as respects solid bodies, requires no 
proof: it is obvious to the touch. With regard to liquids, 
the property may be proved by very simple experiments. 
Let a vessel be filled to the brim with water, and a solid, 
incapable of solution in water, be plunged into it ; a por- 
tion of the water will overflow exactly equal in bulk to 
the body immersed. If a cork be rammed hard into the 
neck of a vial full of water, the vial will burst, while its 
neck remains entire. 

The disposition of air to resist penetration may be 
illustrated in the following way : Let a tall glass vessel 
42^ 2G 



498 HAND-BOOK OF LAND AND MARINE ENGINES. 

be nearly filled with water, on the surface of which a 
lighted taper is set to float ; if over this glass a smaller 
cylindrical vessel, likewise of glass, be inverted and pressed 
downwards, the contained air maintaining its place, the 
internal body of the water will descend while the rest will 
rise up at the sides, and the taper will continue to burn 
for some seconds encompassed by the whole mass of 
liquid. 

Impetus. — Impetus is the product of the mass and 
velocity of a moving body, considered as instantaneous, 
in distinction from momentum, with reference to time, ajid 
force, with reference to capacity of continuing its motion. 
Impetus in gunnery is the altitude through which a heavy 
body must fall to acquire a velocity equal to that with 
which the ball is discharged from the piece. 

Incidence. — The term incidence in mechanics is used 
to denote the direction in which a body or ray of light 
strikes another body, and is otherwise called inclination. 
In moving bodies their incidence is said to be perpendic- 
ular or oblique according as their lines of motion make a 
straight line or an angle at the point of contact. 

Inclination. — Inclination denotes the mutual approach 
or tendency of two bodies, lines, or planes towards each 
other, so that the lines of their direction make at the point 
of contact an angle of greater or less magnitude. 

Inclined Plane. — An inclined plane is one of the 
mechanical powers ; a plane which forms an angle with 
the horizon. The force which accelerates the motion of 
a heavy body on an inclined plane, is to the force of grav- 
ity as the sine of the inclination of the plane to the radius, 
or, as the height of the plane to its length. 

Inertia. — Inertia is that property of matter by which 
it tends when at rest to remain so, and when in motion to 
continue in motion. 



HAND-BOOK OF LAND AND MARINE ENGINES. 499 

Levers. — Levers are classified into three different kinds 
or orders. When the fulcrum is between the force and 
the weight, the lever is called a lever of the first order ; 
when the weight is between the force and the. fulcrum, the 
lever is of the second order ; when the force is between the 
weight and the fulcrum, the lever is of the third order. 
The levers of safety-valves for steam-boilers belong to this 
latter class. 

Machines. — Machines are instruments employed to 
regulate motion so as to save either time or force. The 
maximum effect of machines is the greatest effect which 
can be produced by them. In all machines that work with 
a uniform motion there is a certain velocity, and a certain 
load of resistance that yields the greatest effect, and which 
are therefore more advantageous than any other. 

A machine may be so heavily charged that the motion 
resulting from the application of any given power will be 
but just sufficient to overcome it, tod if any motion ensue, 
it will be very trifling, and therefore the whole effect very 
small. 

And if the machine is very lightly loaded, it may give 
great velocity to the load ; but from the smallness of its 
quantity, the effect may still be very inconsiderable, con- 
sequently between these two loads there must be some 
intermediate one that will render the effect the greatest 
possible. This is equally true in the application of 
animal strength as in machines. The maximum effect of a 
machine is produced when the weight or resistance to be 
overcome is four-ninths of that which the power, when 
fully exerted, is able to balance, or of that resistance 
which is necessary to reduce the machine to rest, and the 
velocity of the part of the machine to which the power is 
applied should be one-third of the greatest velocity of the 
power. 



500 HAND-BOOK OF LAND AND MARINE ENGINES. 

The moving power and the resistance being both given, 
if the machine be so. constructed that the velocity of the 
point to which the power is applied be to the velocity of 
the point to which the resistance is applied as four times 
the resistance to nine times the power, the machine will 
work to the greatest possible advantage. 

This is equally true when applied to the strength of 
animals ; that is, a man, horse, or other animal, will do the 
greatest quantity of work, by continued labor, when his 
strength is opposed to a resistance equal to four-ninths of 
his natural strength, and his velocity equal to one-third of 
his greatest velocity when not impeded. 

Mass. — Mass is the real quantity of matter in a body, 
and is proportioned to weight when compared in one or 
the same locality. Mass is a constant quantity, whilst 
weight varies ^vith the force of gravity which produces it. 

Matter. — Matter is that of which bodies are composed, 
and occupies space. Matter is recognized as substance in 
contradistinction from geometrical quantities and physical 
phenomena, such as color, shadow, light, heat, electricity, 
and magnetism. 

Mechanical Powers. — Mechanical powers are usually 
denominated the lever, inclined plane, wheel and axle, 
pulley, screw, and wedge. 

The wheel and axle is, however, a revolving lever, the 
screw a revolving inclined plane, and the wedge a double 
inclined plane, thus reducing them to three in number, 
viz., lever, inclined plane, and pulley. 

All these machines act on the same fundamental prin- 
ciple of vertical velocities ; accordingly, the weight multi- 
plied into the space it moves through is equal to the power 
multiplied into the space it moves through. 

In all machines a portion of the effect is lost in over- 
coming the friction of the working parts ; but in making 



HAND-BOOK OF LAND AND MARINE ENGINES. 501 

calculations upon them, it is made first as though no fric- 
tion existed, a deduction being afterwards made. 

Rules for Finding the Effects of the Meehanical Powers. 
Inclined Plane. — As the length of the plane is to its height, 
so is the weight to the power. 

Lever. — When the fulcrum (or support) of the lever is 
between the weight and the power, divide the weight to 
be raised by the power, and the quotient is the difference 
of leverage, or the distance from the fulcrum at which the 
power supports the weight. Or, multiply t,he weight by 
its distance from the fulcrum, and the power by its distance 
from the same point, and the weight and power will be to 
each other as their products. 

When the fulcrum is at one extremity of the lever, and 
the power, or the weight, at the other. As the distance 
between the power, or weight, and fulcrum is to the distance 
between the weight, or power, and fulcrum, so is the efiect 
to the power or the power to the effect. 

Screw. — As the screw is an inclined plane wound 
round a cylinder^ the length of the plane is found by 
adding the square of the circumference of the screw to the 
square of the distance between the threads, and taking the 
square root of the sum and the height is the distance 
between the consecutive threads. 

Wedge. — When two bodies are forced from one another 
in a direction parallel to the back of the wedge. As the 
length of the wedge is to half its back, so is the resistance 
to the force. 

Wheel and Axle. — The power multiplied by the radius 
of the wheel is equal to the weight multiplied by the radius 
of the axle ; as the radius of the wheel is to the radius of 
the axle, so is the effect to the power. 

When a series of wheels and axles act upon each other, 
either by belts or teeth, the weight or velocity will be 



502 HAND-BOOK OF LAND AND MARINE ENGINES. 

to the power or unity as the product of the radii, or circum- 
ferences of the wheels, to the product of the radii or 
circumferences of the axles. 

Mechanics. — Mechanics is that branch of natural phil- 
osophy which treats of the three simple physical elements, 
force, motion, and time, with their combinations, constitut- 
ing power, space, and work. 

Modulus. — The modulus of the elasticity of any sub- 
stance is a column of the same substance capable of pro- 
ducing a pressure on its base, which is to the weight 
causing a certain degree of compression as the length of 
the substance is to the diminution of its length. 

Momentum. — Momentum, in mechanics, is the same 
with impetus' or quantity of motion, and is generally 
estimated by the product of the velocity and mass of the 
body. This is a subject which has led to various contro- 
versies between philosophers, some estimating it by the 
mass into the velocity as stated above, while others main- 
tain that it varies as the mass into the square of the velocity. 
But this difference seems to have arisen rather from a 
misconception of the term, than from any other cause. 
Those who maintain the former doctrine, understanding 
momentum to signify the momentary impact, and the 
latter as the sum of all the impulses, tell the motion of the 
body is destroyed. 

Motion. — ^ Motion, in mechanics, is a change of place, 
or it is that affection of matter by which it passes from 
one point of space to another. Motion is of various kinds, 
as follows : 

Absolute motion is the absolute change of place in a 
moving body independent of any other motion whatever ; 
in which general sense, however, it never falls under our 
observation. 

All those motions which we consider as absolute, are in 



HAND-BOOK OF LAND AND MARINE ENGINES. 503 

fact only relative, being referred to the earth, which is 
itsblf in motion. By absolute motion, therefore, we must 
only understand that which is so with regard to some fixed 
point upon the earth, this -being the sense in which it is 
delivered by writers on this subject. 

Accelerated motion is that which is continually receiv- 
ing constant accessions of velocity. 

Angular motion is the motion of a body as referred to 
a centre, about which it revolves. 

Compound motion is that which is produced by two or 
more powers acting in different directions. 

Uniform motion is when a body moves continually with 
the same velocity, passing over equal spaces in equal 
times. 

Natural motion is that which is natural to bodies or 
that which arises from the action of gravity. 

Relative motion is the change of relative place in one 
or more moving bodies. 

Retarded motion is that which suffers continual diminu- 
tion of velocity, the laws of which are the reverse of those 
for accelerated motion. 

Oscillation, Centre of. — The centre of oscillation is 
that point in a vibrating body into which, if the whole 
were concentrated and attached to the same axis of 
motion, it would vibrate in the same time the body does 
in its natural state. The centre of oscillation is situated 
in a right line passing through the centre of gravity, and 
perpendicular to the axis of motion. 

Parallel Motions. — Contrivances of this kind are re- 
quired for the conversion of rotary and alternating an- 
gular motion into rectilineal motion, and the converse ; 
but the absolute necessity there is of guiding the path of 
a piston in a steam-engine has called forth more attention 
to the principles and mechanism of parallel motions than 



504 HAND-BOOK OF LAND AND MARINE ENGINES. 

would otherwise, in all probability, have been awarded to 
the subject for other purposes. 

Motion is expressed by the following terms: Move, 
going, walking, passing, transit, involution and evolution, 
run, locomotion, flux, rolling, flow, sweep, wander, shift, 
flight, current, etc. 

Pendulum. — If any heavy body, suspended by an in- 
flexible rod from a fixed point, be drawn aside from the 
vertical position, and then let fall, it will descend in the 
arc of a circle, of which the point of suspension is the 
centre. On reaching the vertical position, it will have 
acquired a velocity equal to that which it would have 
acquired by falling vertically through the versed sine of 
the arc it has described, in consequence of which it will 
continue to move in the same arc until the whole velocity 
is destroyed ; and if no other force than gravity acted, 
this would take place when the body reached a height on 
the opposite side of the vertical equal to the height from 
which it fell. 

Having reached this height, it would again descend, and 
so continue to vibrate forever; but in consequence of the 
friction of the axis and the resistance of the air, each suc- 
cessive excursion will be diminished, and the body soon be 
brought to rest in the vertical position. A body thus sus- 
pended and caused to vibrate is called a pendulum ; and 
the passage from the greatest distance from the vertical 
on the one side to the greatest distance on the other is 
called an oscillation. 

Percussion. — The centre of percussion is that point 
in a body revolving about an axis at which, if it struck 
an immovable obstacle, all its motion would be destroyed, 
or it would not incline either way. 

When an oscillating body vibrates with a given angular 
velocity, and strikes an obstacle, the effect of the impact 



HAND-BOOK OF LAND AND MARINE ENGINES. 505 

will be the greatest if it be made at the centre of percus- 
sion. For in this case the obstacle receives the whole 
revolving motion of the body ; whereas, if the blow be 
struck in any other point, a part of the motion will be 
employed in endeavoring to continue the rotation. 

Perpetual Motion. — In mechanics, a machine which, 
when set in motion, would continue to move forever, or, at 
least, until destroyed by the friction of its parts, without 
the aid of any exterior cause. The discovery of perpetual 
motion has always been a celebrated problem in mechanics, 
on which many ingenious, though in general ill-instructed, 
persons have consumed their time; but all the labor 
bestowed on it has proved abortive. In fact, the im- 
possibility of its existence has been fully demonstrated 
from the known laws of matter. In speaking of per- 
petual motion, it is to be understood that, from among the 
forces by which motion may be produced, we are to ex- 
clude not only air and water, but other natural agents, as 
heat, atmospheric changes, etc. The only admissible agents 
are the inertia of matter, and its attractive forces, which 
may all be considered of the same kind as gravitation. 

It is an admitted principle in philosophy, that action 
and reaction are equal, and that, when motion is com- 
municated from one body to another, the first loses just as 
much as is gained by the second. But every moving 
body is continually retarded by two passive forces, — the 
resistance of the air and friction. In order, therefore, 
that motion may be continued without diminution, one 
of two things is necessary — either that it be niaintained by 
an exterior force, (in which case it would cease to be what 
we understand by a perpetual motion,) or that the re 
sistance of the air and friction be annihilated, which is 
practically impossible. 

The motion cannot be perpetuated till these retarding 
43 



506 HAND-BOOK OF LAND AND MARINE ENGINES. 

forces are compensated, and they can only be compensated 
by an exterior force, for the force communicated to any 
body cannot be greater than the generating force, and 
this is only sufficient to continue the same quantity of 
motion when there is no resistance. The error of con- 
founding mere pressure with energy available to produce 
power is the main origin of the majority of attempts at 
perpetual motion, and even sometimes causes, among 
confused minds, exaggerating expectations about the 
effects to be obtained from mechanical contrivances. A 
wound-up spring is perfectly equivalent to a weight. It 
may exert a certain pressure, large in proportion to its 
size and strength ; but unless it is allowed to unwind, it 
cannot produce motion or power. It is the same with 
compressed air or gases ; they are in fact nothing but 
wound-up springs, with the difference, however, that, in 
place of needing mechanical power to wind them up, we 
may use either heat, chemical agencies, or electricity. 

Pneumatics. — Pneumatics is the science which treats 
of the mechanical properties of elastic fluids, and particu- 
larly of atmospheric air. Elastic fluids are divided into 
two classes — permanent gases, and vapors. The gases 
cannot be converted into the liquid state by any known 
process of art, whereas the vapors are readily reduced to 
the liquid form by pressure or diminution of temperature. 
In respect of their mechanical properties, there is, how- 
ever, no essential difference between the two classes. 

Elastic fluids, in a state of equilibrium, are subject to 
the action of two forces, namely, gravity, and a molecular 
force acting from particle to particle. 

Gravity acts on the gases in the same manner as on all 
other substances ; but the action of the molecular forces 
is altogether different from that which takes place among 
the elementary particles of solids and liquids ; for, in the 



HAND-BOOK OF LAND AND MARINP: ENGINES. 507 

case of solid bodies, the molecules strougly attract e^ch 
other, (whence results their cohesion,) and, in the case of 
liquids, exert a feeble or evanescent attraction, so as to be 
indifferent to internal motion ; but, in the case of the 
gases, the molecular forces are repulsive, and the molecules, 
yielding to the action of these forces, tend incessantly to 
recede from each other, and, in fact, do recede until their 
further separation is prevented by an exterior obstacle. 

Thus, air confined within a close vessel exerts a con- 
stant pressure against the interior surface, which is not 
sensible, only because it is balanced by the equal pressure 
of the atmosphere on the exterior surface. This pressure 
exerted by the air against the sides of a vessel within which 
it is confined is called its elasticity or elastic force or 
tension. 

Power. — Power is the product of force and velocity ; 
that is to say, a force multiplied by the velocity with 
which it is acting. The term horse-power is a unit of 
power, established by James Watt to be equivalent to a 
force of 33,000 pounds acting with a velocity of one foot 
per minute, or 150 pounds acting wdth a velocity of 220 
feet per minute, which is the same as a force of 550 pounds 
acting with a velocity of one foot per second. Man-power 
is a unit of power established by Morin to be equivalent 
to 50 foot-pounds of power, or 50 effects ; that is to say, a 
man turning a crank with a force of 50 pounds, and with 
a velocity of one foot per second, is a standard man- 
power. 

Prime Movers. — Prime movers are those machines 
from which we obtain power, through their adaptation to 
the transformation of some available natural force into, 
that kind of effort which develops mechanical power. 

Statics is the science of forces in equilibrium. It embraces 
the strength of materials, of bridges, and of girders ; the 



508 HAND-BOOK OF LAND AND MARINE ENGINES. 

Stability of walls, steeples, and towers ; the static momen- 
tum of levers, with their combination into weighing-scales, 
windlasses, pulleys, funicular machines, inclined planes, 
screws, catenaria, and all kinds of gearing. 

Tools. — By the term tools, according to the definition 
given by Rennie, we understand instruments employed in 
the manual arts for facilitating mechanical operations by 
means of percussion, penetration, separation, and abrasion, 
of the substances operated upon, and for all which opera- 
tions various motions are required to be imparted either 
to the tool or to the work. 

Torsion. — Torsion, in mechanics, is the twisting or 
wrenching of a body by the exertion of a lateral force. 
If a slender rod of metal, suspended vertically, and having 
its upper end fixed, be twisted through a certain angle by 
a force acting in a plane perpendicular to its axis, it will, 
on the removal of the force, untwist itself, or return in the 
opposite direction with a greater or less velocity, and after 
a series of oscillations will come to rest in its original 
position. 

The limits of torsion within which the body will return 
to its original state depend on its elasticity. A fine wire 
of a few feet in length may be twisted through several 
revolutions, without impairing its elasticity; and within 
those limits the force evolved is found to be perfectly 
regular, and directly proportional to the angular displace- 
ment from the position of rest. If the angular displace- 
ment exceeds a certain limit (as in a wire of lead, for ex- 
ample, before disruption takes place), the particles will 
assume a new arrangement, or take a set, and will not 
return to their original position On the withdrawal of the 
disturbing force. 

Velocity. — Velocity is rate of motion. Velocity is 
independent of space and time, but in order to obtain its 



HAND-BOOK OF LAND AND MARINE ENGINES. 509 

value or expression as a quantity, we compare space with 
time. Thus, when the value of velocity of a moving body 
is required, we measure a space which the body passes 
through and divide that space with the time of passage, 
and the quotient is the velocity. Velocity, or rate of 
motion, is expressed by a variety of terms : speed, swiftness, 
rapidity, fleetness, speediness, quickness, haste, hurry, race, 
forced, march, gallop, trot, run, rush, scud, dash, spring, etc. 

Weight. — The weight of a body is the force of attraction 
between the earth and that body. The weight of a body 
is greatest at the surface of the earth, and decreases above 
or below that surface. Above the surface, the weight 
decreases as the square of its distance from the centre of 
the earth, and below the surface the weight decreases 
simply as its distance from the centre. 

Weights and Measures. — The weights and measures 
of this country are identical with those of England. In 
both countries they repose, in fact, upon actually existing 
masses of metal (brass), which have- been individually 
declared by law to be the units of the system. In scien- 
tific theory, they are supposed to rest upon a permanent 
and universal law of nature — the gravitation of distilled 
water at a certain temperature and under a certain a-tmos- 
pheric pressure. 

In this aspect, the origination is with the grains, which 
must be such that 252,458 of these units of brass will be 
in just equilibrium with a cubic inch of distilled water ; 
when the mercury stands at 30 inches in a barometer, and 
in a thermometer of Fahrenheit at 62 degrees, both for 
the air and for the water. Unfortunately, the expounders 
of this theory in England used only the generic term brass, 
and failed to define the specific gravity of the metal to be 
employed ; the consequence of this omission is to leave 
room for an error of jj^j^^^j^ in every attempt to reproduce 
43* 



510 HAND-BOOK OF LAND AND MARINE ENGINES. 

or compare the results. This is the minimum possible 
error ; the maximum would be a fraction of the difference 
in specific gravity between the heaviest and lightest brass 
that can be cast. 

Work. — Work is force acting through space, and is 
measured by multiplying the measure of the force by the 
measure of the space. Work is said to be performed when 
a pressure is exerted upon a body, and the body is thereby 
moved through space. 

Work done is expressed by the following terms : hauled, 
dragged, raised, heaved, tilted, broken, crushed, thrown, 
wrought, fermented, labored, etc., or any expression which 
implies the three simple elements of force, velocity, and 
time. Power multiplied by the time of action is work ; work 
divided by time is power. If work was independent of 
time, then any amount of work could be accomplished in 
no time. The greatest amount of work known to have 
been accomplished in the shortest time is that in the ex- 
plosion of nitro-glycerine, which is instantaneous to our 
perception ; but it required time, notwithstanding. 

Wopkmanday. — A laborer working eight hours per 
day can exert a power of 50 foot-pounds. A day's work 
will then be 50 X 8 X 60 X 60 = 1,440,000 foot-pounds of 
work, which may be termed a workmanday. All kinds 
of heavy work can be estimated in workmandays, such as 
the building of a house, a bridge, a steamboat, canal and 
railroad excavations and embankments, loading or unload- 
ing a ship, powder and steam-boiler explosions, and the 
capability of heavy ordnance, etc. 

The magnitude of the unit workmanday is easily con- 
ceived, because it is that amount of work which a laborer 
can accomplish in one day. Work expressed in foot- 
pounds, divided by 1,440,000, gives the work in workman- 
days. 



HAND-BOOK OF LAND AND MARINE ENGINES. 511 

THE CIRCLE. 

The area of any circle is equal to the square of its 
diameter multiplied by •7854 ; it is also equal to its cir- 
cumference multiplied by half its radius. On the prin- 
ciple of the area of a triangle being equal to its base, 
multiplied by half its perpendicular height, a circle may 
be considered as composed of a great many triangles, 
whose bases are the circumference of the circle, and whose 
vertices are coincident with the centre of the circle. 

A TABLE 

CONTAINING THE DIAMETERS, CIRCUMFERENCES, AND AREAS OF 
CIRCLES, AND THE CONTENTS OF EACH IN. GALLONS, AT 1 FOOT 
IN DEPTH. UTILITY OF THE TABLE. 

EXAMPLES. 

1. Required the circumference of a circle, the diameter 
being five inches ? 

In the column opposite the given diameter stands 15*708* 
inches, the circumference required. 

2. Required the capacity in gallons of a can, the di- 
ameter being 6 feet and depth 10 feet? 

In the fourth column from the given diameter stands 
211*4472,* being the contents of a can 6 feet in diameter 
and 1 foot in depth, which being multiplied by 10 gives 
the required contents, 21 14 J gallons. 

3. Any of the areas in feet multiplied by *03704, the 
product equals the number of cubic yards at 1 foot in 
depth. 

4. The area of a circle in inches multiplied by the 
length or thickness in inches, and by .263, the product 
equals the weight in pounds of cast-iron. 

*For decimal equivalents to the fractional parts of a gallon or an 
inch, see table on page 294. 



512 



HAND-BOOK OF LAND AND MARINE ENGINES. 



TABLE 

OF DIAMETERS, CIRCUMFERENCES, AND AREAS OF CIRCLES, AND 
THE CONTENTS IN GALLONS AT 1 FOOT IN DEPTH. 



DiAM. 


Cm. 


Area. 


Gallons. 


DiAM. 


CiR. 


Area. 


Gallons. 


Inch. 


Inch. 


Inch. 




Inch. 


Inch. 


Inch. 




1 


3.1416 


.7854 


.04084 


1 


19.242 


29.464 


1.53213 


i 


3.5343 


.9940 


.05169 




19.635 


30.679 


1.59531 


i 


3.9270 


1.2271 


.06380 


1 


20.027 


31.919 


1.65979 


f 


4.3197 


1.4848 


.07717 


J 


20.420 


33.183 


1.72552 




4.7124 


1.7671 


.09188 


t 


20.813 


34.471 


1.79249 


1 


5.1051 


2.0739 


.10784 


21.205 


35.784 


1.86077 


f 


5.4978 


2.4052 


.12506 


1 


21.598 


37.122 


1.93034 


|- 


5.8905 


2.7611 


.14357 


7 


21.991 


38.484 


2.00117 


2 


6.2832 


3.1416 


.16333 


1 


22.383 


39.871 


2.07329 


i 


6.6759 


3.5465 


.18439 




22.776 


41.282 


2.14666 




7.0686 


3.9760 


.20675 


1 


23.169 


42.718 


2.22134 


1 


7.4613 


4.4302 


.23036 


J 


23.562 


44.178 


2.29726 


J 


7.8540 


4.9087 


.25522 


I 


23.954 


45.663 


2.37448 


1 


8.2467 


5.4119 


.28142 


1 


24.347 


47.173 


2.45299 


4 


8.6394 


5.9395 


.30883 


i 


24.740 


48.707 


2.53276 


-|- 


9.0321 


6.4918 


.33753 


8 


25.132 


50.265 


2.61378 


3 


9.4248 


7.0686 


.36754 


|. 


25.515 


51.848 


2.69609 


^ 


9.8175 


7.6699 


.39879 


1 


25.918 


53.456 


2.77971 


J 


10.210 


8.2957 


.43134 


f 


26.310 


55.088 


2.86458 


1 


10.602 


8.9462 


.46519 


4 


26.703 


56.745 


2.95074 


i 


10.995 


9.6211 


.50029 


_ 


27.096 


58.426 


3.03815 


5 


11.388 


10.320 


.53664 


|. 


27.489 


60.132 


3.12686 


1 


11.781 


11.044 


.57429 


- 


27.881 


61.862 


3.21682 


i 


12.173 


11.793 


.61324 


9 


28.274 


63.617 


3.30808 


4 


12.566 


12.566 


.65343 


i 


28.667 


65.396 


3.40059 


i 


12.959 


13.364 


.69493 




29.059 


67.200 


3.49440 


i 


13.351 


14.186 


.73767 


- 


29.452 


69.029 


3.58951 


f 


13.744 


15.033 


.78172 


^ 


29.845 


70.882 


3.68586 


1 


14.137 


15.904 


.82701 


5 


30.237 


72.759 


3.78347 




14.529 


16.800 


.87360 


1 


30.630 


74.662 


3.88242 


1 


14.922 


17.720 


.92144 


8" 


31.023 


76.588 


3.98258 


i 


15.315 


18.665 


.97058 


10 


31.416 


78.540 


4.08408 


5 


15.708 


19.635 


1.02102 


i 


31.808 


80.515 


4.18678 


1 


16.100 


20.629 


1.07271 




32.201 


82.516 


4.29083 




16.493 


21.647 


1.12564 


- 


32.594 


84.540 


4.39608 


1 


16.886 


22.690 


1.17988 


J 


32.986 


86.590 


4.50268 


} 


17.278 


23.758 


1.23542 


_ 


33.379 


88.664 


4.61053 


|. 


17.671 


24.850 


1.29220 


1 


33.772 


90.762 


4.71962 


1 


18.064 


25.967 


1.35028 


i 


34.164 


92.885 


4.82846 


I 


18.457 


27.108 


1.40962 


11 


34.557 


95.033 


4.94172 


6 


18.849 


28.274 


1.47025 


4 


34.950 


97.205 


5.05466 



HAND-BOOK OF LAND AND MARINE ENGINES. 



513 



T A B L E — ( Continued) 

OF DIAMETERS^ CIRCUMFERENCES, AND AREAS OF CIRCLES, AND 
THE CONTENTS IN GALLONS AT 1 FOOT IN DEPTH. 



DiAM. 

Inch. 


ClR. 


Akea. 


Gallons. 


DiAM. 


Cm. 


Area. 


Gallons. 


Inch. 


Inch. 




Inch. 


Inch. 


Inch. 




1 


35.343 


99.402 


5.16890 


3 


10 


12 5J 


11.5409 


86.3074 




35.735 


101.623 


5.28439 


3 11 


12 


12.0481 


90.1004 


i 


36.128 


103.869 


5.40119 


4 




12 6| 


12.5664 


93.9754 


1 


36.521 


106.139 


5.51923 


4 


1 


12 9J 


13.0952 


97.9310 


1 


36.913 


108.434 


5.63857 


4 


2 


13 1 


13.6353 


101.9701 


^ 


37.306 


110.753 


5.75916 


4 


3 


13 4i 


14.1862 


103.0300 










4 


4 


13 71 


14.7479 


110.2907 


Ft In. 


Ft. In. 


Feet. 




4 


6 


1310J 


15.3206 


114.5735 


1 


3 If 


.7854 


5.8735 


4 


6 


14 1| 


15.9043 


118.9386 


1 1 


3 4| 


.9217 


6.8928 


4 


7 


14 4| 


16.4986 


123.3830 


1 2 


3 8 


1.0690 


7.9944 


4 


8 


14 7i 


17.1041 


127.9112 


1 3 


3 11 


1.2271 


9.1766 


4 


9 


1411 


17.7205 


132.5209 


1 4 


4 2J 


1.3962 


10.4413 


4 10 


15 2J 


18.3476 


137.2105 


1 5 


4 5| 


1.5761 


11.7866 


4 11 


15 6i 


18.9858 


142.0582 


1 6 


4 8-i 


1.7671 


13.2150 


5 




15 8i 


19.6350 


146.8384 


1 7 


4 111 


1.9689 


14.7241 


5 


1:15 111 


20.2947 


151.7718 


1 8 


5 2f 


2.1816 


16.3148 


5 


216 2f 


20.9656 


156.7891 


1 9 


5 5| 


2.4052 


17.9870 


5 


3 16 5| 


21.6475 


161.8886 


1 10 


5 9 


2.6398 


19.7414 


5 


416 9 


22.3400 


167.0674 


1 11 


6 2} 


2.8852 


21.4830 


5 


517 Oi 


23.0437 


172.3300 


2 


6 3i 


3.1416 


23.4940 


5 


6 


17 3} 


23.7583 


177.6740 


2 1 


6 6J 


3.4087 


25.4916 


5 


7 


17 6f 


24.4835 


183.0973 


2 2 


6 9| 


3.6869 


27.5720 


5 


8 


17 9| 


25.2199 


188.6045 


2 3 


7 Of 


3.9760 


29.7340 


5 


9 


18 Of 


25.9672 


194.1930 


2 4 


7 3i 


4.2760 


32.6976 


5 


10 


18 3| 


26.7251 


199.8610 


2 5 


7 7 


4.5869 


34.3027 


5 


11 


18 71 


27.4943 


205.6133 


2 6 


7 lOi 


4.9087 


36.7092 


6 




18 lOJ 


28.2744 


211.4472 


2 7 


8 If 


5.2413 


39.1964 


6 


3 


19 7^ 


30.6796 


229.4342 


2 8 


8 4^ 


5.5850 


41.7668 


6 


6 


20 ^ 


33.1831 


248.1564 


2 9 


8 7| 


5.9395 


44.4179 


6 


9 


21 21 


35.7847 


267.6122 


2 10 


8 lOf 


6.3049 


47.1505 


7 




21 IH 


38.4846 


287.8032 


2 11 


9 H 


6.6813 


49.9654 


7 


3 


22 91 


41.2825 


308.7270 


3 


9 5 


7.0686 


52.8618 


7 


6 


23 6f 


44.1787 


330.3859 


3 1 


9 8} 


7.4666 


55.8382 


7 


9 


24 4^ 


47.1730 


352.7665 


3 2 


9 111 


7.8757 


58.8976 


8 




25 li 


50.2656 


375.9062 


3 3 


10 2J 


8.2957 


62.0386 


8 


3 


2511 


53.4562 


399.7668 


3 4 


10 5| 


8.7265 


65.2602 


8 


6 


26 8| 


56.7451 


424.3625 


3 5 


10 8f 


9.1683 


68.5193 


8 


9 


27 5| 


60.1321 


449.2118 


3 6 


10 111 


9.6211 


73.1504 


9 




28 3i 


63.6174 


475.7563 


3 7 


11 3 


10.0846 


^ 75.4166 


9 


3 


29 0^ 


67.2007 


502.5536 


3 8 


11 6i 


10.5591 


78.9652 


9 


6 


29 lOJ 


70.8823 


530.0861 


3 9 


11 n 


11.0446 


82.5959 


9 


9 


30 7i 


74.6620 


558.3522 



2H 



514 



HAND-BOOK OP LAND AND MAHINE ENGINES. 



T A 'Blj'B — (Concluded) 

OF DIAMETERS, CIRCUMFERENCES, AND AREAS OF CIRCLES, AND 
THE CONTENTS IN GALLONS AT 1 FOOT IN DEPTH. 



DiAM. 

Ft. In. 


Cm. 


Area. 


Gallons. 


DiAM. 

Ft. In. 


CiR. 


Area. 


Gallons. 


Ft. In. 


Feet. 




Ft. In. 


Feet. 




10 


31 5 


78.5400 


587.3534 


20 


6 


64 4| 


330.0643 2468.3528 


10 3 


32 2| 


82.5160 


617.0876 


20 


9 


65 2J 


338.1637 2528.9233 


10 6 


32 llj 


86.5903 


647.5568 


21 




65111 


346.3614|2590.2290 


10 9 


33 9\ 


90.7627 


678.2797 


21 


3 


66 9 


354.6571 


2652.2532 


11 


34 61 


95.0334 


710.6977 


21 


6 


67 6i 


363.0511 


2715.0413 


11 3 


35 41 


99.4021 


743.3686 


21 


9 


68 31 


371.5432 


2778.5486 


11 6 


36 U 


103.8691 


776.7746 


22 




69 If 


380.1336 


2842.7910 


11 9 


36 10| 


108.4342 


810.9143 


22 


3 


69101 


388.8220 


2907.7664 


12 


37 8| 


113.0976 


848.1890 


22 


6 


70 8i 


397.6087 


2973.4889 


12 3 


38 5f 


117.8590 


881.3966 


22 


9 


71 51 


406.4935 


3039.9209 


12 6 


39 3i 


122.7187 


917.7395 


23 




72 3 


415.4766 


3107.1001 


12 9 


40 0| 


127.6765 


954.8159 


23 


3 


73 Oi 


424.5577 


3175.0122 


13 


40 10 


132.7326 


992.6274 


23 


6 


73 9J 


433.7371 


3243.6595 


13 3 


41 7^ 


137.8867 


1031.1719 


23 


9 


74 7i 


443.0146;3313.0403 


13 6 


42 4j 


143.1391 


1070.4514 


24 




75 4f 


452.3904:3383.1563 


13 9 


43 2j 


148.4896 


1108.0645 


24 


3 


76 2i 


461.8642 3454.0051 


14 


43 11$ 


153.9384 


1151.2129 


24 


6 


76 111 


471.4363'3525.5929 


14 3 


44 9J 


159.4852 


1192.6940 


24 


9 


77 9 


481.1065|3597.9068 


14 6 


45 6| 


165.1303 


1234.9104 


25 




78 6f 


490.8750 3670.9596 


14 9 


46 4 


170.8735 


1277.8615 


25 


3 


79 3s 


500.7415i3744.7452 


15 


47 li 


176.7150 


1321.5454 


25 


6 


80 li 


510.7063|3819.2657 


15 3 


47 lOf 


182.6545 


1365.9634 


25 


9 


8010} 


520.7692 3894.5203 


15 6 


48 8} 


188.6923 


1407.5165 


26 




81 8i 


530.930413970.5098 


15 9 


49 5| 


194.8282 


1457.0032 


26 


3 


82 5i- 


541.1896 


4047.2322 


16 


50 3i 


201.0624 


1503.6250 


26 


6 


83 3 


551.5471 


4124.6898 


16 3 


51 OJ 


207.3946 


1550.9797 


26 


9 


84 Of 


562.0027 


4202.9610 


16 6 


51 10 


213.8251 


1599.0696 


27 




84 9i 


572.5566i4281.8072 


16 9 


52 7| 


220.3537 


1647.8930 


27 


3 


85 8J 


583.2085 4361.4664 


17 


53 4i 


226.9806 


1697.4516 


27 


6 


86 4| 


593.9587 4441.8607 


17 3 


54 2i 


233.7055 


1747.7431 


27 


9 


87 2i 


604.8070i4522.9886 


17 6 


54 111 


240.5287 


1798.7698 


28 




87 1H 


615.7536 


4604.8517 


17 9 


55 91 


247.4500 


1850.5301 


28 


3 


88 9 


626.7982 


4686.4876 


18 


56 6J 


254.4696 


1903.0254 


28 


6 


89 6^ 


637.9411 


4770.7787 


18 3 


57 4 


261.5872 


1956.2537 


28 


9 


90 3- 


649.1821 


4854.8434 


18 6 


58 If 


268.8031 


2010.2171 


29 




91 1 


660.5214 


4939.6432 


18 9 


58 10} 


276.1171 


2064.9140 


29 


3 


91101 


671.9587 


5025.1759 


19 


59 8i 


283.5294 


2120.3462 


29 


6 


92 Sh 


683.4943 


5111.4487 


19 3 


60 5| 


291.0397 


2176.5113 


29 


9 


93 5J 


695.1280 


5198.4451 


19 6 


61 3i 


298.6483 


2233.2914 


30 




94 2i 


706.8600 


5286.1818 


19 9 


62 0^ 


306.3550 


2291.0452 


30 


8 


95 Of 


718.6900 


5374.6512 


20 


62 9i 


314.1600 


2349.4141 


30 


6 


95 9} 


730.6183 


5463.8558 


20 3163 1 


322.0630 


2408.5159 


30 


9 


96 7i 


742.6447 


5553.7940 



HAND-BOOK OF LAND AND MARINE ENGINES. 515 

LOGARITHMS. 

The logarithm of a number is the exponent of a power 
to which another given invariable number must be raised in 
order to produce the first number. Thus, in the common 
system of logarithms, in which the invariable number is 
10, the logarithm of 1000 is 3, because 10 raised to the third 
power is 1000. In general, if a' = y, in which equation a 
is a given invariable number, then x is the logarithm of y. 
All absolute numbers whether positive or negative, whole 
or fractional, may be produced by raising an invariable 
number to suitable powers. The invariable number is 
called the base of the system of logarithms ; it may be any 
number whatever greater or less than unity ; but having 
been once chosen, it must remain the same for the forma- 
tion of all numbers in the same system. Whatever number 
may be selected for the base, the logarithm of the base is 
1, and the logarithm of 1 is 0. 

These properties of logarithms are of very great im- 
portance in facilitating the arithmetical operations of 
multiplication and division. For, if a multiplication is 
to be effected, it is only necessary to take from the loga- 
rithmic tables the logarithms of the factors, and add them 
into one sum, which gives the logarithm of the required 
product ; and, on finding in the table the number corre- 
sponding to this new logarithm, the product itself is ob- 
tained. Thus, by means of a table of logarithms, the 
operation of multiplication is performed by simple addi- 
tion. In like manner, if one number is to be divided by 
another, it is only necessary to subtract the logarithm of 
the divisor from that of the dividend, and to find in the 
table the number: corresponding to this difference, which 
number is the quotient required. Thus, the quotient of a 
division is obtained by simple subtraction. 



516 



HAND-BOOK OF LAND AND MARINE ENGINES. 



LOGAEITHMS OF NUMBEES FEOM TO 1000* 



No. 





1 


2 


3 


4 


5 


6 


7 


8 


9 


1 





1 
00000 30103 


47712 


60206 


69897 77815 


84510 


90309 


95424 




10 


00000 00432 1 


00860 


01283 


01703 


02118 02530 


02938 


03342 


03742 


415 


11 


04139 04532! 


04921 


05307 


05690 


06069 06445 


06818 


07188 


07554 


379 


12 


07918 08278 


08636 


08990 


09342 


09691 10037 


10380 


10721 


11059 


a49 


13 


11394 11727 


12057 


12385 


12710 


13033 13353 


13672 


13987 


14301 


323 


14 


14613 14921 


15228 


15533 


15836 


16136 16435 


16731 


17026 


17318 


300 


15 


17609 17897 


18184 


18469 


18752 


19033 19312 


19590 


19865 


20139 


281 


16 


20412 20682 


20951 


21218 


21484 


21748 22010 


22271 


22530 


22788 


264 


17 


23045 


23299 


23552 


23804 


24054 


24303 24551 


24797 


25042 


25285 


249 


18 


25527 


25767 


26007 


26245 


26481 


26717 26951 


27184 


27415 


27646 


236 


19 


27875 


28103 


28330 


28555 


28780 


29003 29225 


29446 


29666 


29885 


223 


20 


30103 


30319 


30535 


30749 


30963 


31175 31386 


31597 


31806 


32014 


212 


21 


3?2?^ 


32428 


32633 


32838 


33041 


33243 33445 


33646 


33845 


34044 


202 


22 


34242 


34439 


^635 


34830 


35024 135218 35410 


35602 


35793 


35983 


194 


23 


36173 


36361 


36548 


36735 


36921 37106 37291 


37474 


37657 37839 


185 


24 


38021 


38201 


38381 


38560 


38739 38916 39093 


39269 


39445 39619 


177 


25 


39794 


39967 


40140 


40312 


40483 '40654 40824 


40993 


41162 41330 


171 


26 


41497 


41664 


41830 


41995 


42160 ,42324 42488 


42651 


42813 42975 


164 


27 


43436 


43296 


43456 


43616 


43775 43933 44090 


44248 


44404 44560 


158 


28 


44716 


44870 


45024 


45178 


45331 i 45484 , 45636 


45788 


45939 46089 


153 


29 


46240 


46389 


46538 


46686 


468^4 46982 47129 


47275 


47421 47567 


148 


30 


47712 


47856 


48000 


48144 


48287 ; 48430 


48572 


48713 


48855 ' 48995 


143 


31 


49136 


49276 


49415 


49554 


49693 49831 


49968 


50105 


50242 50379 


138 


32 


50515 


50650 


50785 


50920 


51054 51188 


51321 


51454 


51587 i 51719 


134 


33 


51851 


51982 


52113 


52244 


52374 '52504 


52633 


52763 


52891 53020 


130 


34 


53148 


53275 


53102 


53529 


53655 '53781 


53907 


54033 


54157 i 54282 


126 


35 


54407 


54,530 


54654 


54777 


54900 55022 


55145 


55266 


55388 55509 


122 


36 


55630 


55750 


55870 


55990 


56410 ; 56229 


56348 


56466 


56584 56702 


119 


37 


56820 


56937 


57054 


57170 


57287 '57403 


57518 


57634 


57749 57863 


116 


38 


57978 


58002 


58206 


58319 


58433 ,58546 


58658 


58771 


58883 58995 


113 


39 


59106 


59217 


59328 


59439 


59549 59659 


59769 


59879 


59988 60097 


110 


40 


60206 


60314 


60422 


60530 


60638 60745 


60852 


60959 


61066 61172 


107 


41 


61278 


61384 


61489 


61595 


61700 '61804 


61909 


62013 


62117 62221 


104 


42 


62325 


62428 


62531 


62634 


62736 '62838 


62941 


63042 


63144 63245 


102 


43 


63347 


63447 


63548 


63648 


63749 63848 


63948 ' 64048 


64147 


64246 


99 


44 


64345 


64443 


64542 


64640 


64738 64836 


64933 i 65030 


65127 


65224 


98 


45 


65321 


65417 


65513 


65609 


65075 ,65801 


65896 1 65991 


66086 


66181 


96 


46 


66276 


66370 


66464 


66558 


66651 


66745 


66838 


66931 


67024 


67117 


94 


47 


67210 


67302 


67394 


67486 


67577 


67669 


67760 


67851 


67942 


68033 


92 


48 


68124 


68214 


68304 


68394 


68484 


68574 


68663 


68752 


68842 


68930 


90 


49 


69020 


69108 


69196 


69284 


69372 


69460 69548 


69635 


69722 


69810 


88 


50 


69897 


69983 


70070 


70156 


70243 


70329 : 70415 


70500 


70586 


70671 


86 


51 


70757 


70842 


70927 


71011 


71096 


71180 


71265 


71349 


71433 


71516 


84 


52 


71600 


71683 


71767 


71850 


71933 


72015 


72098 


72181 


72263 


72345 


82 


53 


72428 


72509 


72591 


72672 


72754 


72835 


72916 


72997 


73078 


73158 


81 


54 


73239 


73319 


73399 


73480 


73559 


73639 


73719 


73798 


73878 


73957 


80 


55 


74036 


74115 


74193 


74272 


74351 


74429 


74507 


74585 


74663 


74741 


78 


56 


74818 


74896 


74973 


75050 


75127 


75204 


75281 


75358 


75434 


75511 


77 


57 


75587 


75663 


75739 


75815 


75891 


75966 


76042 i 76117 


76192 


76267 


75 


58 


76342 


76417 


76492 


76566 


76641 


76715 ' 76789 ,' 76863 


76937 


77011 


74 


59 


77085 


77158 


77232 


77305 


77378 


77451 77524 77597 


77670 


77742 


73 


60 


77815 


77887 


77959 


78031 


78103 


78175 78247 178318 


78390 


78461 


72 


61 


78533 


78604 


78675 


78746 


78816 


78887 78958 79028 


79098 


79169 


71 


62 


79239 


79309 


79379 


79448 


79518 


79588 79657 ' 79726 


79796 


79865 


70 


63 


799^4 

4^ 


80002 


80071 


80140 


80208 


80277 80345,80413 

i 1 


80482 


80550 


69 



^ Each logarithm is supposed to have the decimal sign . before it. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



517 



LOGAKITHMS OF NUMBEKS FKOM TO 1000. 
(Continued.) 



No. 





1 


2 


3 


4 


5 


6 


7 


S 


9 


i 


64 


80618 


80685 


80753 


80821 


80888 


80956 


81023 


81090. 


81157 


81224 


68 


65 


81291 


81358 


81424 


81491 


81557 


81624 


81690 


81756 


81822 


81888 


67 


66 


81954 


82020 


82085 


82151 


82216 


82282 


82347 


82412 


82477 


82542 


66 


67 


82607 


82672 


82736 


82801 


82866 


82930 


82994 83058 


83123 


83187 


65 


68 


83250 


83314 


83378 


83442 i 83505 1 83569 


83632 83695 


83758 


83821 


64 


69 


83884 


83947 


84010 


84073 


84136 84198 


84260 84323 


84385 


84447 


63 


70 


84509 


84571 


84633 


84695 


84757 [ 84818 


84880 , 84941 


85003 


85064 


62 


71 


85125 


85187 


85248 


85309 


85369 


85430 


85491 


85551 


85612 


85672 


61 


72 


85733 


85793 


85853 


85913 


85973 


86033 


86093 


86153 


86213 


86272 


60 


73 


86332 


86391 


86451 


86510 


86569 


86628 


86687 


86746 


86805 


8686i 


59 


74 


86923 


86981 


87040 


87098 


87157 


87215 


87273 


87332 


87390 


87448 


58 


75 


87506 


87564 


87621 


87679 


87737 


87794 


87852 


87909 


87966 


88024 


57 


76 


88081 


88138 


88195 


88252 


88309 


88366 


88422 


88479 


88536 


88592 


56 


77 


88649 


88705 


88761 


88818 


88874 


88930 


88986 


89042 


89098 


89153 


56 


78 


89209 


89265 


89320 


89376 i 89431 


89487 


89542 


89597 


89652 


89707 


55 


79 


89762 


89817 


89872 89927 


89982 


90036 


90091 


90145 


90200 


90254 


54 


80 


90309 


90363 


90417 


90471 


90525 


90579 


90633 


90687 


90741 


90794 


54 


81 


90848 


90902 


90955 


91009 


91062 


91115 


91169 


9122? 


91275 


91328 


53 


82 


91381 


91434 


91487 


91540 


91592 


.91645 


91698 


91750 


91803 


91855 


53 


83 


91907 


91960 


92012 


92064 


92116 


92168 


92220 


92272 


92324 


92376 


52 


84 


92427 


92479 1 92531 


92582 


92634 


92685 


92737 


92788 


92839 


92890 


51 


85 92941 


92993 


93044 


93095 


93146 


93196 


93247 


93298 


93348 


93399 


51 


86 


93449 


93500 


93550 


93601 


93651 


93701 


93751 


93802 


93852 


93902 


50 


87 


93951 


94001 


94051 


94101 


94151 


94200 


94250 


94300 


94349 


94398 


49 


88 


94448 


94497 


94546 


94596 


94645 


94694 


94743 


94792 


94841 


94890 


49 


89 


94939 


94987 


95036 


95085 


95133 


95182 


95230 


95279 


95327 


95376 


48 


90 


95424 


95472 


95520 


95568 


95616 


95664 


95712 


95760 


95808 


95856 


48 


91 


95904 


95951 


95999 


96047 


96094 


96142 


96189 


96236 


96284 


96331 


48 


92 


96378 


96426 


96473 


96520 


96507 


96614 


96661 


96708 


96754 


96801 


47 


93 


96848 


96895 


96941 


96988 


97034 


97081 


97127 


97174 


97220 


97266 


47 


94 


97312 


97359 


97405 


97451 


97497 


97543 


97589 


97635 


97680 


97726 


46 


95 


97772 


97818 


97863 


97909 


97954 


98000 


98045 


98091 


98136 


98181 


46 


96 


98227 


98272 


98317 


98362 


98407 


98452 


98497 


98542 


98587 


98632 


45 


97 


98677 


98721 


98766 


98811 


98855 


98900 


98945 


98989 


99033 


99078 


45 


98 


99122 


99166 


99211 


99255 


99299 


99343 


99387 


99431 


99475 


99519 


44 


99 


99563 


99607 


99657 


99694 


99738 


99782 


99825 


99869 


99913 


99956 


44 



HYPERBOLIC LOGARITHMS. 

Hyperbolic logarithms is a system of logarithms so 
called because the numbers express the areas between the 
asymptote and curve of the hyperbola. The hyperbolic 
logarithm of any number is to the common logarithm of 
the same number in the ratio of 2*30258509 to 1, or as 1 
to -43429448. 
44 



518 



HAND-BOOK OF LAND AND MARINE ENGINES. 



TABLE 

OF HYPERBOLIC LOGARITHMS. 



Num. 


Log. 


Num. 


Log. 


Num. 


Log. 


Num. 


Log. 


1.01 


.0099 


1.43 


.3576 


1.85 


.6151 


2.27 


.8197 


1.02 


.0198 


1.44 


.3646 


1.86 


.6205 


2.28 


.8241 


1.03 


.0295 


1.45 


.3715 


1.87 


.6269 


2.29 


.8285 


1.04 


.0392 


1.46 


.3784 


1.88 


.6312 


2.30 


.8329 


1.06 


.0487 


1.47 


.3862 


1.89 


.6365 


2.31 


.8372 


1.06 


.0582 


1.48 


.3920 


1.90 


.6418 


2.32 


.8415 


1.07 


.0676 


1.49 


.3987 


1.91 


.6471 


2.33 


.8458 


1.08 


.0769 


1.60 


.4054 


1.92 


.6623 


2.34 


.8601 


1.09 


.0861 


1.61 


.4121 


1.93 


.6576 


2.35 


.8544 


1.10 


.0953 


1.52 


.4187 


1.94 


.6626 


2.36 


.8686 


1.11 


.1043 


1.53 


.4252 


1.95 


.6678 


2.37 


.8628 


1.12 


.1133 


1.54 


.4317 


1.96 


.6729 


2.88 


.8671 


1.13 


.1222 


1.65 


.4382 


1.97 


.6780 


2.39 


.8712 


1.14 


,1310 


1.56 


.4446 


1.98 


.6830 


2.40 


.8764 


1.15 


.1397 


1.57 


.4510 


1.99 


.6881 


2.41 


.8796 


1.16 


.1484 


1.58 


.4574 


2.00 


.6931 


2.42 


.8837 


1.17 


.1570 


1.69 


.4637 


2.01 


.6981 


2.43 


.8878 


1.18 


.1655 


1.60 


.4700 


2.02 


.7030 


2.44 


.8919 


1.19 


.1739 


1.61 


.4762 


2.03 


.7080 


2.45 


.8960 


1.20 


.1823 


1.62 


.4824 


2.04 


.7129 


2.46 


.9001 


1.21 


.1962 


1.63 


.4885 


2.05 


.7178 


2.47 


.9042 


1.22 


.1988 


1.64 


.4946 


2.06 


.7227 


2.48 


.9082 


1.23 


.2070 


1.65 


.5007 


2.07 


.7275 


2.49 


.9122 


1.24 


.2151 


1.66 


.5068 


2.08 


.7323 


2.60 


.9162 


1.25 


.2231 


1.67 


.5128 


2.09 


.7371 


2.51 


.9202 


1.26 


.2341 


1.68 


.5187 


2.10 


.7419 


2.52 


.9242 


1.27 


.2390 


1.69 


.5247 


2.11 


.7466 


2.63 


.9282 


1.28 


.2468 


1.70 


.5306 


2.12 


.7514 


2.64 


.9321 


1.29 


.2546 


1.71 


.5364 


2.13 


.7561 


2.55 


.9360 


1.30 


.2623 


1.72 


.5423 


2.14 


.7608 


2.66 


.9400 


1.31 


.2700 


1.73 


.6481 


2.15 


.7654 


2.57 


.9439 


1.32 


.2776 


1.74 


.5538 


2.16 


.7701 


2.68 


.9477 


1.33 


.2851 


1.75 


.5696 


2.17 


.7747 


2.59 


.9516 


1.34 


.2926 


1.76 


.5663 


2.18 


.7793 


2.60 


.9655 


1.35 


.3001 


lw7 


.5709 


2.19 


.7839 


2.61 


.9593 


1.36 


.3074 


1.78 


.6763 


2.20 


.7884 


2.62 


.9631 


1.37 


.3148 


1.79 


.6822 


2.2L 


.7929 


2.63 


.9669 


1.38 


.3220 


1.80 


.5877 


2.22 


.79.76 


2.64 


.9707 


1.39 


.3293 


1.81 


.5933 


2.23 


.8021 


2.65 


.9745 


1.40 


.3364 


1.82 


.6988 


2.24 


.8064 


2.66 


.9783 


1.41 


.3435 


1.83 


.6043 


2.25 


.8109 


2.67 


.9820 


1.42 


.3506 


1.84 


.6097 


2.26 


.8153 


2.68 


.9858 



HAND-BOOK OF LAND AND MARINE ENGINES. 



519 



T A B L K — iCorUinued) 
OF HYPERBOLIC LOGARITHMS. 



Num. 


Log. 


Num. 


•Log. 


Num. 


Log. 


Num. 


Log. 


2.69 


.9895 


3.11 


1.1346 


3.53 


1.2612 


3.95 


1.3737 


2.70 


.9932 


3.12 


1.1378 


3.54 


1.2641 


8.96 


1.8726 


2.71 


.9969 


3.18 


1.1410 


3.55 


1.2669 


3.97 


1.3787 


2.72 


1.0006 


3.14 


1.1442 


3 56 


1.2697 


3.98 


1.8812 


2.78 


1.0043 


8.15 


1.1474 


3.57 


1.2725 


3.99 


1.8887 


2.74 


1.0079 


3.16 


1.1505 


3.58 


1.2753 


4.00 


1.8862 


2.75 


1.0116 


3.17 


1.1537 


3.59 


1.2781 


4.01 


1.8887 


2.76 


1.0152 


8.18 


1.1568 


3.60 


1.2809 


4.02 


1.3912 


2.77 


1.0188 


8.19 


1.1600 


3.61 


1.2887 


4.03 


1.8937 


2.78 


1.0224 


3.20 


1.1681 


3.62 


1.2864 


4.04 


1.3962 


2.79 


1.0260 


8.21 


1.1662 


3.68 


1.2892 


4.05 


1.3987 


2.80 


1.0296 


3.22 


1.1693 


3.64 


1.2919 


4.06 


1.4011 


2.81 


1.0381 


3.23 


1.1724 


3.65 


1.2947 


4.07 


1.4086 


2.82 


1.0367 


3.24 


1.1755 


3.66 


1.2974 


4.08 


1.4060 


2.83 


1.0402 


8.25 


1.1786 


3 67 


1.8001 


4.09 


1-4085 


2.84 


1.0488 


3.26 


1.1817 


3.68 


1.3029 


4.10 


1.4109 


2.85 


1.0473 


8.27 


1.1847 


3.69 


1.3056 


4.11 


1.4184 


2.86 


1.0508 


8.28 


1.1878 


3.70 


1.3088 


4.12 


1.4158 


2.87 


1.0543 


3.29 


1.1908 


3.71 


1.3110 


4.13 


1.4182 


2.88 


1.0577 


3.80 


1.1939 


3.72 


1.8187 


4.14 


1.4206 


2.89 


1.0612 


3.31 


1.1969 


3.73 


1.8164 


4.15 


1.4281 


2.90 


1.0647 


3.82 


1.1999 


3.74 


1.8190 


4.16 


1.4255 


2.91 


1.0681 


3.33 


1.2029 


8.75 


1.3217 


4.17 


1.4279 


2.92 


1.0715 


3.34 


1.2059 


3.76 


1.3244 


4.18 


1.4303 


2.93 


1.0750 


8.85 


1.2089 


3.77 


1.3271 


4.19 


1.4327 


2.94 


1.0784 


3.86 


1.2119 


3.78 


1.3297 


4.20 


1.4350 


2.95 


1.0818 


3,37 


1.2149 


3.79 


1.8323 


4.21 


1.4374 


2.96 


1.0851 


8.38 


1.2178 


3.80 


1.3350 


4.22 


1.4398 


2.97 


1.0885 


8.39 


1.2208 


8.81 


1.3876 


4.23 


1.4421 


2.98 


1.0919 


8.40 


1.2237 


3.82 


1.3402 


4.24 


1.4445 


2.99 


1.0952 


3.41 


1.2267 


3.83 


1.3428 


4.25 


1.4469 


8.00 


1.0986 


3.42 


1.2296 


3.84 


1.3454 


4.26 


1.4492 


3.01 


1.1019 


3.43 


1.2325 


3.85 


1.3480 


4.27 


1.4516 


3.02 


1.1052 


3.44 


1.2854 


3.86 


1.3506 


4.28 


1.4539 


3.03 


1.1085 


8.45 


1.2887 


8.87 


1.3582 


4.29 


1.4662 


3.04 


1.1118 


8.46 


1.2412 


3.88 


1.8658 


4.30 


1.4586 


3.05 


1.1151 


3.47 


1.2441 


8.89 


1.8584 


4.31 


1.4609 


8.06 


1.1184 


3.48 


1.2470 


3.90 


1.3609 


4.82 


1.4682 


3.07 


1.1216 


3.49 


1.2499 


3.91 


1.3635 


4.88 


1.4655 


3.08 


1.1249 


3.50 


1.2527 


3.92 


1.3660 


4.84 


1.4678 


3.09 


1.1281 


3.51 


1.2556 


3.93 


1.8686 


4.35 


1.4701 


3.10 


1.1314 


3.52 


1.2584 


3.94 


1.3711 


4.36 


1.4724 



520 



HAND-BOOK OF LAND AND MARINE ENGINES. 



T A B L Jj^—iOmcluded) 
OF HYPERBOLIC LOGARITHMS. 



Num. 


Log. 


Num. 


Log. 


Num. 


Log. 


Num. 


Log. 


4.37 


1.4747 


4.79 


1.5665 


5.21 


1.6505 


5.63 


1.7281 


4.38 


1.4778 


4.80 


1.5686 


5.22 


1.6524 


5.64 


1.7298 


4.39 


1.4793 


4.81 


1.5706 


5.23 


1.6544 


5.65 


1.7316 


4.40 


1.4816 


4.82 


1.5727 


5.24 


1.6563 


5.66 


1.7334 


4.41 


1.4838 


4.83 


1.5748 


5.25 


1.6582 


5.67 


1.7351 


4.42 


1.4838 


4.84 


1.5769 


5.26 


1.6601 


5.68 


1.7389 


4.43 


1.4883 


4.85 


1.5789 


5.27 


1.6620 


5.69 


1.7387 


4.44 


1.4906 


4.86 


1.5810 


5.28 


1.6639 


5.70 


1.7404 


4.45 


1.4929 


4.87 


1.5830 


5.29 


1.6658 


5.71 


1.7422 


4.46 


1.4914 


4.88 


1.5851 


5.30 


1.667.7 


5.72 


1.7439 


4.47 


1.4973 


4.89 


1.5870 


6.31 


1.6695 


5.73 


1.7457 


4.48 


1.4996 


4.90 


1.5892 


5.32 


1.6714 


5.74 


1.7474 


4.49 


1.5018 


4.91 


1.5912 


5.33 


1.6733 


5.75 


1.7491 


4.50 


1.5040 


4.92 


1.5933 


5.34 


1.6752 


5.76 


1.7509 


4.51 


1.5062 


4.93 


1.5953 


5.35 


1.6770 


5.77 


1.7526 


452 


1.5085 


4.94 


1.5973 


5.36 


1.6789 


5.78 


1.7544 


4.53 


1.5107 


4.95 


1.5993 


5.37 


1.6808 


5.79 


1.7561 


4.54 


1.5129 


4.96 


1.6014 


5.38 


1.6826 


5.80 


1.7578 


4.55 


1.5151 


4.97 


1.6034 


5.39 


1.6845 


5.81 


1.7595 


4.56 


1.5173 


4.98 


1.6054 


5.40 


1.6863 


5.82 


1.7613 


4.57 


1.5195 


4.99 


1.6074 


5.41 


1.6882 


5.83 


1.7630 


4.58 


1.5216 


5.00 


1.6094 


5.42 


1.6900 


5.84 


1.7647 


4.59 


1.5238 


5.01 


1.6114 


5.43 


1.6919 


5.85 


1.7664 


4.60 


1.5260 


5.02 


1.6134 


5.44 


1.6937 


5.86 


1.7681 


4.61 


1.5-282 


5.03 


1.6154 


5.45 


1.6956 


5.87 


1.7698 


4.62 


1.5303 


5.04 


1.6174 


5.46 


1.6974 


5.88 


1.7715 


4.63 


1.5325 


5.05 


1.6193 


5.47 


1.6992 


5.89 


1.7732 


4.64 


1.5347 


5.06 


1.6213 


5.48 


1.7011 


5.90 


1.7749 


4.65 


1.5368 


5.07 


1.6233 


5.49 


1.7029 


5.91 


1.7766 


4.66 


1.5390 


5.08 


1.6253 


5.50 


1.7047 


5.92 


1.7783 


4.67 


1.5411 


5.09 


1.6272 


5.51 


1.7065 


5.93 


1.7800 


4.68 


1.5432 


5.10 


1.6292 


5.52 


1.7083 


5.94 


1.7817 


4.69 


1.5454 


5.11 


1.6311 


5.53 


1.7101 


5.95 


1.7833 


4.70 


1.5475 


5.12 


1.6331 


5.54 


1-7119 


5.96 


1.7850 


4.71 


1.5496 


5.13 


1.6351 


5.55 


1.7137 


5.97 


1.7867 


4.72 


1.5518 


5.14 


1.6370 


5.56 


1.7155 


5.98 


1.7884 


4.73 


1.5539 


5.15 


1.6389 


5.57 


1.7173 


5.99 


1.7900 


4.74 


1.5560 


5.16 


1.6409 


5.58 


1.7191 


6.00 


1.7917 


4.75 


1.5581 


5.17 


1.6428 


5.59 


1.7209 


6.01 


1.7934 


4.76 


1.5602 


5.18 


1.6448 


5.60 


1.7227 


6.02 


1.7950 


4.77 


1.5623 


5.19 


1.6463 


5.61 


1.7245 


6.03 


1.7967 


4.78 


1.5644 


5.20 


1.6486 


5.62 


1.7263 


6.04 


1.7989 



HAND-BOOK OF LAND AND MARINE ENGINES, 



521 



TABLE 

CONTAINING THE DIAMETERS, CIRCUMFERENCES, AND AREAS OF 
CIRCLES FROM -^-^ OF AN INCH TO 100 INCHES, ADVANCING BY 
yV OF AN INCH UP TO 10 INCHES, AND BY J OF AN INCH FROM 
10 TO 100 INCHES. 



DiAM. 


CiRCUM. 


Area. 


DiAM. 


CiRCUM. 


Area. 


iDCh. 






Inch. 






A 


.1963 


.0030 


A 


7.6576 


4.6664 


i 


.3927 


.0122 


i 


7.8540 


4.9087 


A 


.5890 


.0276 


A 


8.0503 


5.1573 


i 


.7854 


.0490 


f 


8.2467 


5.4119 


A 


.9817 


.0767 


H 


8.4430 


5.6727 




1.1781 


.1104 


i 


8.6394 


5.9395 


A 


1.3744 


.1503 


ii 


8.8357 


6.2126 


^ 


1.5708 


.1963 


i 


9.0321 


6.4918 


A 


1.7671 


.2485 


H 


9.2284 


6.7772 


f 


1.9635 


.3068 


3 


9.4248 


7.0686 


a 


2.1598 


.3712 


A 


9.6211 


7.3662 


f 


2.3562 


.4417 


i- 


9.8175 


7.6699 


¥ 


2.5525 


.5185 


A 


10.0138 


7.9798 


2.7489 


.6013 


i 


10.2120 


8.2957 


ii 


2.9452 


.6903 


A 


10.4065 


8,6179 


1 


3.1416 


.7854 


f 


10.6029 


8.9462 


A 


3.3379 


.8861 


A 


10.7992 


9.2806 


i 


3.5343 


.9940 


i 


10.9956 


9.6211 


A 


3.7306 


1.1075 


A 


11.1919 


9.9678 


i 


3.9270 


1.2271 


1 


11.3883 


10.3206 


A 


4.1233 


1.3529 


H 


11.5846 


10.6796 


f 


4.3197 


1.4848 


i 


11.7810 


11.0446 


A 


4.5160 


1.6229 


? 


11.9773 


11.4159 


i 


4.7124 


1.7671 


12.1737 


11.7932 


A 


4.9087 


1.9175 


H 


12.3700 


12.1768 


1 


5.1051 


2.0739 


4 


12.5664 


12.5664 


H 


5.3014 


2.2365 


A 


12.7627 


12.9622 


f 


5.4978 


2.4052 


t 


12.9591 


13.3640 


H 


5.6941 


2.5801 




13.1554 


13,7721 


? 


5.8905 


2.7611 


13.3518 


14.1862 


if 


6.0868 


2.9483 


A 


13.5481 


14.6066 


2 


6.2832 


3.1416 


f 


13.7445 


15.0331 


A 


6.4795 


3.3411 


A 


13.9408 


15.4657 


i 


6.6759 


3.5465 


i 


14.1372 


15.9043 


t 


6.8722 


3.7582 


A 


14.3335 


16.3492 


7.0686 


3.9760 


1 


14.5299 


16.8001 


A 


7.2640 


4.2001 


? 


14.7262 


17.2573 


I 


7.4613 


4.4302 


14.9226 


17.7205 



522 HAND-BOOK OF LAND AND MARINE ENGINES, 



TABLE — iOontinued) 
CONTAINING THE DIAM., CIRCUMFERENCES, AND AREAS OF CIRCLES. 



DiAM. 


CiRCUM. 


Area. 


DiAM. 


CiRCUM. 


Area. 


Inch. 






Inch. 






if 


15.1189 


18.1900 


A 


23.3656 


43.4455 


i 


15.3153 


18.6655 


J 


23.5620 


44.1787 


H 


15.5716 


19.1472 


A 


23.7583 


44.9181 


5 


15.7080 


19.6350 


1 


23.9547 


45.6636 


iV 


15.9043 


20.1290 


tt 


24.1510 


46.4153 


i 


16.1007 


20.6290 


i 


24.3474 


47.1730 


A 


16.2970 


21.1252 


¥ 


24.5437 


47.9370 


i 


16.4934 


21.6475 


24.7401 


48.7070 


A 


16.6897 


22.1661 


if 


24.9364 


49.4833 


1 


16.8861 


22.6907 


8 


25.1328 


50.2656 


A 


17.0824 


23.2215 


A 


25.3291 


51.0541 


i 


17.2788 


23.7583 


i 


25.5255 


51.8486 


A 


17.4751 


24.3014 


A 


25.7218 


52.8994 


f 


17.6715 


24.8505 


i 


25.9182 


53.4562 


H 


17.8678 


25.4058 


A 


26.1145 


54.2748 


i 


18.0642 


25.9672 


1 


26.3109 


65.0885 


If 


18.2605 


26.5348 




26.5072 


55.9138 


•i 


18.4569 


27.1085 


^ 


26.7036 


56.7451 


i* 


18.6532 


27.6884 


t\ 


26.8999 


57.5887 


6 


18.8496 


28.2744 


f 


27.0963 


58.4264 


A 


19.0459 


28.8665 


H 


27.2926 


59.7762 


i 


19.2423 


29.4647 


1 


27.4890 


60.1321 


A 


19.4386 


30.0798 


f 


27.6853 


60.9943 


V 


19.6350 


30.6796 


27.8817 


61.8625 


A 


19.8313 


31.2964 


it 


28.0780 


62.7369 


1 


20.0277 


31.9192 


9 


28.2744 


63.6174 


A 


20.2240 


32.5481 


A 


28.4707 


64.5041 




20.4204 


33.1831 


* 


28.6671 


65.3968 


A 


20.6167 


33.8244 


A 


28.8634 


66.2957 


f 


20.8131 


34.4717 


i 


29.0598 


67.2007 


H 


21.0094 


35.1252 


A 


29.2561 


68.1120 


f 


21.2058 


35.7847 


1 


29.4525 


69.0293 


« 


21.4021 


36.4505 


A 


29.6488 


69.9528 


i 


21.5985 


37.1224 


i 


29.8452 


70.8823 


if 


21.7948 


37.8005 


A 


30.0415 


71.8181 


7 


21.9912 


38.4846 


1 


30.2379 


72.7599 


A 


22.1875 


39.1749 


H 


30.4342 


73.7079 


i 


22.3839 


39.8713 


* 


30.6306 


74.6620 


A 


22.5802 


40.5469 


if 


30.8269 


75.6223 


i 


22.7766 


41.2825 


1 


31.0233 


76.5887 


A 


22.9729 


41.9974 


if 


31.2196 


77.5613 


I 


23.1693 


42.7184 


10 


31.4160 


78.5400 



HAND-BOOK OF LAND AND MARINE ENGINES. 



523 



T A B L E — ( Continued) 
CONTAINING THE'DIAM., CIRCUMFERENCES, AND AREAS OF CIRCLES. 



DiAM. 


CiRCUM. 


Area. 


DiAM. 


CiRCUM. 


Area. 


Inch. 






Inch. 






: 


31.8087 


80.5157 


1 


48.3021 


185.6612 




32.2014 


82.5160 


5" 


48.6948 


188.6923 


J . 


32.5941 


84.5409 


A 


49.0875 


191.7480 


5" 


32.9868 


86.5903 


J 


49.4802 


194.8282 


1 

8" 


33.3795 


88.6643 


"8 


49.8729 


197.9330 




33.7722 


90.7627 


16 


50.2656 


201.0624 


1 • 
8" 


34.1649 


92.8858 


J 


50.6583 


204.2162 


11 


34.5576 


95.0334 


i 


51.0510 


207.3946 




34.9503 


97.2053 


1 


51.4437 


210.5976 


1 


35.3430 


99.4021 


1 


51.8364 


213.8251 


1 


35.7357 


101.6234 




52.2291 


217.0772 


^ 


36.1284 


103.8691 


J 


52.6218 


220.3537 


1 


36.5211 


106.1394 


1 


53.0145 


223.6549 




36.9138 


108.4342 


17 


53.4072 


226.9806 


37.3065 


110.7536 


i 


53.7999 


230.3308 


1^2 


37.6992 


113.0976 




54.1926 


233.7055 


i 


38.0919 


115.4660 


i- 


54.5853 


237.1049 




38.4846 


117.8590 


^ 


54.9780 


240.5287 


■^ 


38.8773 


120.2766 


4 


55.3707 


243.9771 


1 ■ 


39.2700 


122.7187 


J 


55.7634 


247.4500 


1 


39.6627 


125.1854 


- 


56.1561 


250.9475 




40.0554 


127.6765 


18 


56.5488 


254.4696 


■g" 


40.4481 


130.1923 


X 


56.9415 


258.0161 


13 


40.8408 


132.7326 


1 


57.3342 


261.5872 


1 


41.2338 


135.2974 


^ 


57.7269 


265.1829 


J. 


41.6262 


137.8867 


^ 


58.1196 


268.8031 


1 


42.0189 


140.5007 


2^ 


58.5123 


272.4479 


5- 


42.4116 


143.1391 


58.9056 


276.1171 


1 


42.8043 


145.8021 


•g- 


59.2977 


279.8110 


i 


43.1970 


148.4896 


19 


59.6904 


283.5294 


43.5897 


151.2017 


i 


60.0831 


287.2723 


14 


43.9824 


153.9384 


J 


60.4758 


291.0397 


i 


44.3751 


156.6995 


f 


60.8685 


294.8312 


i 


44.7676 


159.4852 


i 


61.2612 


298.6483 


K 


45.1605 


162.2956 


5 

■g- 


61.6539 


302.4894 


X 


45.5532 


165.1303 


a 

1 


62.0466 


306.3550 


1 


45.9459 


167.9896 


62.4393 


310.2452 


■g- 


46.3386 


170.8735 


20 


62.8320 


314.1600 


46.7313 


173.7820 


^ 


63.2247 


318.0992 


15 


47.1240 


176.7150 


^ 


63.6174 


322.0630 


J. 


47.5167 


179.6725 


f 


64.0101 


326.0514 


J 


47.9094 


182.6545 


h 


64.4028 


330.0643 



524 



HAND-BOOK OF LAND AND MARINE ENGINES. 



T A B L E — (Cbw/ini/€d:) 

CONTAINING THE DIAM., CIRCUMFERENCES, AND AREAS OF CIRCIiES. 



DiAM. 


CiRCUM. 


Area. 


DiAM. 


CiRCUM. 


Area. 


Inch. 






Inch. 






5 


64.7955 


334.1018 


i 


81.2889 


525.8375 


J 


65.1882 


338.1637 


26 


81.6816 


530.9304 


|- 


65.5809 


342.2503 




82.0743 


536.0477 


21 


65.7936 


346.3614 


; ■ 


82.4670 


541.1896 




66.3663 


350.4970 




82.8597 


546.3561 


. . 


66.7590 


354.6571 




83.2524 


551.5471 


" ■ 


67.1517 


358.8419 


- 


83.6451 


556.7627 


i 


67.5444 


363.0511 




84.0378 


562.0027 




67.9371 


367.2849 


84.4305 


567.2674 


J 


68.3298 


371.5432 


2^7 


84.8232 


572.5566 


-7 


68.7225 


375.8261 


;■ 


85.2159 


577.8703 


22 


69.1152 


380.1336 




85.6086 


583.2085 


]■ 


69.5079 


384.4655 




86.0013 


588.5714 




69.9006 


388.8220 


■ ■ 


86.3940 


593.9587 


'. ' 


70.2933 


393.2031 




86.7867 


599.3706 


- ■ 


70.6860 


397.6087 


: ' 


87.1794 


604.8070 


■ 


71.0787 


402.0388 


r 


87.5721 


610.2680 




71.4714 


406.4935 


28 


87.9648 


615.7536 


■ " 


71.8641 


410.9728 


4 


88.3575 


621.2636 


23 


72.2568 


415.4766 


J 


88.7502 


626.7982 


i 


72.6495 


420.0049 


1 


89.1429 


632.3574 


J. 


73.0422 


424.5577 


; ■ 


89.5356 


637.9411 


1 


73.4349 


429.1352 


1 


89.9283 


643.5494 


^ 


73.8276 


433.7371 


J 


90.3210 


649.1821 


5 


74.2203 


438.3636 


8 


90.7137 


654.8395 


4 


74.6130 


443.0146 


29 


91.1064 


660.5214 


^ 


75.0057 


447.6992 


^ 


91.4991 


666.2278 


24 


75.3984 


452.3904 


J 


91.8918 


671.9587 


i 


75.7911 


457.1150 


1 


92.2845 


677.7143 


i 


76.1838 


461.8642 


I 


92.6772 


683.4943 




76.5765 


466.6380 


f 


93.0699 


689.2989 


^ 


76.9692 


471.4363 




93.4626 


695.1280 


1 


77.3619 


476.2592 


i 


93.8553 


700.9817 


1 


77.7546 


481.1065 


30 


94.2480 


706.8600 


-I 


78.1473 


485.9785 


i 


94.6407 


712.7627 


25 


78.5400 


490.8750 


1 


95.0334 


718.6900 


i 


78.9327 


495.7960 


* 


95.4261 


724.6419 


i 


79.3254 


500.7415 




95.8188 


730.6183 




79.7181 


505.7117 


^ 


96.2115 


736.6193 


J 


80.1308 


510.7063 


} 


96.6042 


742.6447 


-| ■ 


80.5035 


515.7255 


96.9969 


748.6948 


« 


80.8962 


520.7692 


31 


97.3896 


754.7694 



HAND-BOOK OF LAND AND MARINE ENGINES. 



525 



TABLE — (Continued) 

CONTAINING THE DIAM.. CIRCUMFERENCES, AND AREAS OF CIRCLES. 



DiAM. 


CiRCUM. 


Area. 


DiAM. 


CiRCUM. 


Area. 


Inch. 






Inch. 






i 


97.7823 


760.8685 


f 


114.2757 


1039.1946 


-- 


98.1750 


766.9921 




114.6684 


1046.3941 


f 


98.5677 


773.1404 


115.0611 


1053.5281 




98.9684 


779.3131 


J 


115.4538 


1060.7317 


-| 


99.3531 


785.5104 


i 


115.8465 


1067.9599 


1 


99.7458 


791.7322 


37 


116.2392 


1075.2126 


i 


100.1385 


797.9786 


1 


116.6319 


1082.4898 


32 


100.5312 


804.2496 


J 


117.0246 


1089.7915 


i 


100.9240 


810.5450 


I 


117.4173 


1097.1179 


i 


101.3166 


816.8650 


J 


117.8100 


1104.4687 


1 


101.7093 


823.2096 


-| 


118.2027 


1111.8441 


i 


102.1020 


829.5787 


j 


118.5954 


1119.2440 


¥ 


102.4947 


835.9724 


118.9881 


1126.6685 




102.8874 


842.3905 


38 


119.3808 


1134.1176 


i 


103.2801 


848.8333 


-g- 


119.7735 


1141.5911 


33 


103.6728 


855.3006 


1 


120.1662 


1149.0892 


1 


104.0655 


861.7924 


-^ 


120.5589 


1156.6119 


J 


104.4582 


868.3087 


^ 


120.9516 


1164.1591 


8. 


104.8509 


874.8497 


8 


121.3443 


1171.7309 


^ 


105.2436 


881.4151 




121.7370 


1179.3271 


■| 


105.6363 


888.0051 


■J 


122.1297 


1186.9480 


J 


106.0290 


894.6196 


39 


122.5224 


1194.5934 


1 


106.4217 


901.2587 


J 


122.9151 


1202.2633 


34 


106.8144 


907.9224 


I 


123.3078 


1209.9577 


1 


107.2071 


914.6105 


~ 


123.7005 


1217.6768 


^ - 


107.5998 


921.3232 


^ 


124.0932 


1225.4203 


^ 


107.9925 


928.0605 


-5. 

8 


124.4859 


1233.1884 


^ 


108.3852 


934.8223 




124.9787 


1240.9810 


4- 


108.7779 


941.6086 


l 


125.2713 


1248.7982 


^ 


109.1706 


948.4195 


40 


125.6640 


1256.6400 


¥ 


109.5633 


955.2550 


^ 


126.0567 


1264.5062 


35 


109.9560 


962.1150 


J 


126.4494 


1272.3970 


- 


110.3487 


968.9995 


1 


126.8421 


1280.3124 


i 


110.7414 


975.9085 


J 


127.2348 


1288.2523 


^ 


111.1341 


982.8422 


|- 


127.6275 


1296.2168 


J 


111.5268 


989.8003 


1 


128.0202 


1304.2057 


1 


111.9195 


996.7830 


i 


128.4129 


1312.2193 


J 


112.3122 


1003.7902 


41 


128.8056 


1320.2574 


|- 


112.7049 


1010.8220 


■g. 


129.1983 


1328.3200 


36 


113.0976 


1017.8784 


'■■ 


129.5910 


1336.4071 


i 


113.4903 


1024.9592 


1 


129.9837 


1344.5189 


i 


113.8830 


1032.0646 


i 


130.3764 


1352.6551 



526 



HAND-BOOK OF LAND AND MARINE ENGINES. 



TABLE — (Continued) 
CONTAINING THE DIAM., CIRCUMFERENCES, AND AREAS OF CIRCLES. 



DiAM. 


CiRCUM. 


Area. 


DiAM. 


CiRCUM. 


Area. 


Inch. 






Inch. 






1 


130.7691 


1360.8159 


i 


147.2625 


1725.7324 


* 

5" 


131.1618 


1369.0012 


47 


147.6552 


1734.9486 


131.5545 


1377.2111 


_ 


148.0479 


1744.1893 


42 


131.9472 


1385.4456 


;■ 


148.4406 


1753.4545 


i 


132.3399 


1393.7045 


^ 


148.8333 


1762.7344 


1 


132.7326 


1401.9880 


^ 


149.2260 


1772.0587 




133.1253 


1410.2961 


f 


149.6187 


1781.3976 


^ 


133.5180 


1418.6287 


f 


150.0114 


1790.7610 


1 


133.9107 


1426.9859 


i 


150.4041 


1800.1490 




134.3034 


1435.3675 


48 


150.7968 


1809.5616 


134.6961 


1443.7738 


1 


151.1895 


1818.9986 


43 


135.0888 


1452.2046 


4 


151.5822 


1828.4602 


I 


135.4815 


1460.6599 


1 


151.9749 


1837.9364 


i- 


135.8742 


1469.1397 


J 


152.3676 


1847.4571 


f 


136.2669 


1477.6342 


-| 


152.7603 


1856.9924 




136.6596 


1486.1731 


f 


153.1530 


1868.5521 


-| 


137.0523 


1494.7266 


i 


153.5457 


1876.1365 


j 


137.4450 


1503.3046 


49 


153.9384 


1885.7454 


i 


137.8377 


1511.9072 


i 


154.3311 


1895.3788 


44 


138.2304 


1520.5344 


i 


154.7238 


1905.0367 


i 


138.6231 


1529.1860 


f 


155.1165 


1914.7093 


i 


139.0158 


1537.8622 




155.5092 


1924.4263 


f 


139.4085 


1546.5530 


-| 


155.9019 


1934.1579 




139.8012 


1555.2883 


1 


156.2946 


1943.9140 


I 


140.1939 


1564.0382 


156.6873 


1953.6947 


J 


140.5866 


1572.8125 


50 


157.0800 


1963.5000 


1- 


140.9793 


1581.6115 




157.4727 


1973.3297 


45 


141.3720 


1590.4350 


-- 


157.8654 


1983.1840 


i 


141.7647 


1599.2830 


- 


158.2581 


1993.0529 


J 


142.1574 


1608.1555 




158.6508 


2002.9663 


1 


142.5501 


1617.0427 


1 


159.0435 


2012.8943 


i 


142.9428 


1625.9743 


1 


159.4362 


2022.8467 


1 


143.3355 


1634.9205 


i 


159.8289 


2032.8238 


f 


143.7382 


1643.8912 


51 


160.2216 


2042.8254 


i 


144.1209 


1652.8865 


i 


160.6143 


2052.8515 


46 


144.5136 


1661.9064 


i 


161.0070 


2062.9021 


i 


144.9063 


1670.9507 


1 


161.3997 


2072.9764 


^ 


145.2990 


1680.0196 




161.7924 


2083.0771 


f 


145.6917 


1689.1031 


1 


162.1851 


2093.2014 




146.0844 


1698.2311 


i 


162.5778 


2103.3502 


"8 


146.4771 


1707.3737 




162.9705 


2113.5236 


f 


146.8698 


1716.5407 


52 


163.3632 


2123.7216 



HAND-BOOK OP LAND AND MARINE ENGINES. 



527 



TABLE "(Continued) 

CONTAINING THE DIAM., CIRCUMFERENCES, AND AREAS OF CIRCLES. 



DiAM. 



Inch. 



f 
i 

7 

¥ . 

53 

I 



8 

54 

i 

X 
4 
3. 



3. 

4 

i 

55 

i 



56 

i 
i 



•g- 
57 



CiRCUM. 



163.7559 
164.1486 
164.5413 
164.9340 
165.3267 
165.7194 
166.1121 
166.5048 
166.8975 
167.2902 
167.6829 
168.0756 
168.4683 
168.8610 
169.2537 
169.6464 
170.0391 
170.4318 
170.8245 
171.2172 
171.6099 
172.0026 
172.3593 
172.7880 
173.1807 
173.5734 
173.9661 
174.3588 
174.7515 
175.1442 
175.5369 
175.9296 
176.3323 
176.7150 
177.1077 
177.5004 
177.8931 
178.2858 
178.6785 
179.0712 
179.4639 
179.8566 



Area. 


DiAM. 




Inch. 


2133.9440 


■| 


2144.1910 


J 


2154.4626 


1 


2164.7587 




2175.0794 


l 


2185.4245 


58 


2195.7943 


i 


2206.1886 


i 


2216.6074 


t 


2227.0507 


i 


2237.5187 


1 


2248.0111 




2258.5281 


|- 


2269.0696 


59 


2279.6357 


i 


2290.2264 




2300.8415 


' ^ 


2311.4812 


2" 


2322.1455 


- 


2332.8343 




2343.5477 


1 


2354.2855 


60 


2365.0480 


I 


2375.8350 




2386.6465 


■| 


2397.4825 


J 


2408.3432 


1 


2419.2283 




2430.1833 


|- 


2441.0772 


61 


2452.0310 


i 


2463.0144 


i 


2474.0222 


i 


2485.3546 




2496.1116 


1 


2507.1931 


1 


2518.2992 


TT 


2529.4297 


62 


2543.5849 


1 


2551.7646 




2562.9688 


1 


2574.1975 


i 



ClRCUM. 



180.2493 

180.6423 

181.0347 

181.4274 

181.8201 

182.2128 

182.6055 

182.9982 

183.3909 

183.7836 

184.1763 

1*84 5690 

184.9617 

185.3544 

185.7471 

186.1398 

186.5325 

186.9252 

187.3179 

187.7106 

188.1033 

188.4960 

188.8887 

189.2814 

189.6741 

190.0668 

190.4595 

190.8522 

191.2419 

191.6376 

192.0303 

192.4230 

192.8157 

193.2084 

193.6011 

193.9931 

194.3865 . 

194.7792^ 

195.1719 

195.5646 

195.9573 

196.3500 



Area. 



2585.4509 
2596.7287 
2608.0311 
2619.3580 
2630.7095 
2642.0856 
2653.4861 
2664.9112 
2676.3609 
2687.8351 
2699.3338 
2710.8571 
2722.4050 
2733.9774 
2745.5743 
2757.1957 
2768.8418 
2780.5123 
2792.2074 
2803.9270 
2815.6712 
2827.4400 
2839.2332 
2851.0510 
2862.8934 
2874.7603 
2886.6517 
2898.5677 
2910.5083 
2922.4734 
2934.4630 
2946.4771 
2958.5139 
2970.5791 
2982.6669 
2994.7792 
3006.9161 
3019.0776 
3031.2635 
3043.4740 
3055.7091 
3067.9687 



528 



HAND-BOOK OF LAND AND MARINE ENGINES. 



T AB L E— (Omttnwed) 

CONTAINING THE DIAM., CIRCUMFERENCES, AND AREAS OF CIRCLES. 



1 



DiAM. 



Inch. 

f 
i 

i 

63 

i 



64 



i 

7 
8 

65 

i 



66 
i 
i 
I 

I 



8 

67 



CiRCUM. 



196.7427 
197.1354 
197.5281 
197.9208 
198.3135 
198.7062 
199.0989 
199.4916 
199.8843 
200.2770 
200.6697 
201.0624 
201.4551 
201.8478 
202.2405 
202.6332 
203.0259 
203.4186 
203.8113 
204.2040 
204.5917 
204.9894 
205.3821 
205.7748 
206.1675 
206.5602 
206.9529 
207.3456 
207.7383 
208.1310 
208.5237 
208.9164 
209.3091 
209.7018 
210.0945 
210,4872 
210.8799 
211.2726 
211.6653 
212.0580 
212.4507 
212.8434 



Area. 


DiAM. 




Inch. 


3080.2529 


* 


3092.5615 


68 


3104.8948 


t 


3117.2526 




3129.6349 


■| 


3142.0417 


2" 


3154 4732 


i 


3166.9291 




3179.4096 


^ 


3191.9146 


69 


3204.4442 


i 


3216.9984 




3229.5770 


4 


3242.1782 


J 


3254.8080 


1 


3267.4603 


2. 


3280.1372 


i 


3292.8385 


70 


3305.5645 


■g" 


3318.3151 




3331.0900 


- 


3343.8875 


2" 


3356.7137 


1 


3369.5623 


1 


3382.4355 


■g- 


3395.3332 


71 


3408.2555 


^ 


3421.2024 


J 


3434.1737 


^ 


3447.1676 


■^ 


3468.1901 


•| 


3473.2351 


i 


3486.3047 


8" 


3499.3987 


72 


3512.5174 


j- 


3525.6606 


J. 


3538.8283 


1 


3552.0185 


^ 


3565.2374 


J 


3578.4787 


J 


3591.7446 


i 


3605.0350 


73 



CiRCUM. 



213.2361 
213.6288 
214.0215 
214.4142 
214.8069 
215.1996 
215.5923 
215.9850 
216.3777 
216.7704 
217.1631 
217.5558 
217.9485 
218.3412 
218.7339 
219.1266 
219.5193 
219.9120 
220.3047 
220.6974 
221.0901 
221.4828 
221.8755 
222.2682 
222.6609 
223.0536 
223.4463 
223.8390 
224.2317 
224.6244 
225.0171 
225.4098 
225.8025 
226.1952 
226.5879 
226.9806 
227.3733 
227.7660 
228.1587 
228.5514 
228.9441 
229.3368 



Area. 



3618.3300 
3631.6896 
3645.0536 
3658.4402 
3671.8554 
3685.2931 
3698.7554 
3712.2421 
3725.7535 
3739.2894 
3752.8498 
3766.4327 
3780.0443 
3793.6783 
3807.3369 
3821.0200 
3834.7277 
3848.4600 
3862.2167 
3875.9960 
2889.8039 
3903.6343 
3917.4893 
3931.3687 
3945.2728 
3959.2014 
3973.1545 
3987.1301 
4001.1344 
4015.1611 
4029.2124 
4043.2882 
4057.3886 
4071.5136 
4085.6631 
4099.8350 
4114.0356 
4128.2587 
4142.5064 
4156.7785 
4171.0753 
4185.3966 



HAND-BOOK OF LAND AND MARINE ENGINES. 



529 



T A B L "Ei— (Continued) 

CONTAINING THE DIAM., CIRCUMFERENCES, AND AREAS OF CIRCLES. 



DiAM. 


CiRCUM. 


Area. 


DiAM. 


CiRCUM. 


Area. 


Inch. 






Inch. 






-g. 


229.7295 


4199.7424 


I 


246.2229 


4824.4299 


I 


230.1222 


4214.1107 


^ 


246.6156 


4839.8311 


- 


230.5149 


4228.5077 


i 


247.0083 


4855.2568 


^ 


230.9076 


4242.9271 


i 


247.4010 


4870.7071 


■| 


231.3003 


4257.3711 


i 


247.7937 


4886.1820 


J 


231.6930 


4271.8396 


79 


248.1864 


4901.6814 


t 


232.0857 


4286.3327 


1 


248.5791 


4917.2053 


74 


232.4784 


4300.8504 




248.9718 


4932.7517 


^ 


232.8711 


4315.3926 


1 


249.3645 


4948.3268 




233.2638 


4329.9572 


^ 


249.7572 


4963.9243 


^ 


233.6565 


4344.5505 


% 


250.1499 


4979.5456 


i 


234.0492 


4359.1663 




250.5426 


4995.1930 


i 


234.4419 


4373.8067 


^ 


250.9353 


5010.8642 




234.8346 


4388.4715 


80 


251.3280 


5026.5600 


i 


235.2273 


4403.1610 


i 


251.7207 


5042.2803 


75 


235.6200 


4417.8750 


i 


252.1134 


5058.0230 




236.0127 


4432.6135 


f 


252.5061 


5073.7944 


J 


236.4054 


4447.3745 


1 


252.8988 


5089.5883 


g 


236.7981 


4462.1642 




253.2915 


5106.4060 


^ 


237.1908 


4476.9763 


1 


253.6842 


5121.2497 




237.5835 


4491.8130 


I 


254.0769 


5137.1173 


J 


237.9762 


4506.6742 


81 


254.4696 


5153.0094 


■g" 


238.3689 


4521.5600 


i 


254.8623 


5168.9260 


76 


238.7616 


4536.4704 


i 


255.2550 


5184.8651 


■g- 


239.1543 


4551.4023 


1 


255.6477 


5200.8329 


J 


239.5470 


4566.3626 




256.0404 


5216.8231 


1 


239.9397 


4581.3486 


I 


256.4331 


5232.8371 


1 


240.3324 


4596.3571 


i 


256.8258 


5248.8772 


1 


240.7251 


4611.3902 


i 


257.2105 


5264.9411 


} 


241.1178 


4626.4477 


82 


257.6112 


5281.0296 


i 


241.5105 


4641.3299 


1 


258.0039 


5297.1426 


77 


241.9032 


4656.6366 


258.3966 


5313.2780 


i 


242.2959 


4671.7678 


f 


258.7893 


5329.4421 


i 


242.6886 


4686.9215 




259.1820 


5345.6287 


1 


243 0813 


4702.1039 


1 


259.5747 


5361.8391 


i 


243.4740 


4717.3087 


* 


259.9674 


5378.0755 




243.8667 


4732.5381 


i 


260.3601 


5394.3358 


1 


244.2594 


4747.7920 


83 


260.7528 


5410.6206 


1 


244.6521 


4763.0705 


J 


261.1455 


6426.9299 


78 


245.0448 


4778.3736 


4 


261.5382 


5443.2617 


I 


245.4375 


4793.7012 


1 


261.9309 


5459.6222 


} 


245.8302 


4809.0512 


i 


262.3236 


5476.0051 



45 



21 



530 



HAND-BOOK OF LAND AND MARINE ENGINES. 



TABLE- iConiinued) 
CONTAINING THE DIAM., CIRCUMFERENCES, AND AREAS OF CIRCLES. 



Dtam. 


CiRCUM. 


Area. 


DiAM. 


CiRCUM. 


Area. 


Inch. 






Inch. 






f 


262.7163 


5492.4118 


i 


279.2097 


6203.6905 


_ 


263.1090 


5508.8446 


89 


279.6024 


6221.1534 


■g" 


263.5017 


5525.3012 


^ 


279.9951 


6238.6408 


84 


263.8944 


5541.7824 


^ 


280.3878 


6256.1507 


i 


264.2871 


5558.2881 


■| 


280.7805 


6273.6893 




264.6?98 


5574.8162 


I 


281.1732 


6291.2503 


1 


265.0725 


5591.3730 


■ i 


281.5659 


6308.8351 




265.4652 


5607.9523 


1 


281.9586 


6326.4460 


A 


265.8579 


5624.5554 


1 


282.3513 


6344.0807 


1 


266.2506 


5641.1845 


90 


282.7440 


6361.7400 


i 


266.6433 


5657.8357 


i 


283.1367 


6379.4238 


85 


267.0360 


5674.5150 


i 


283.5294 


6397.1300 


i 


267.4287 


5691.2170 


« 


283.9221 


6414.8649 




267.8214 


5707.9415 




284.3148 


6432.6223 


- 


268.2141 


5724.6947 


^ 


284.7075 


6450.4039 


i 


268.6068 


5741.4703 


|. 


285.1002 


6468.2107 


h. 

g 


268.9997 


5758.2697 


J 


285.4929 


6486.0418 




269.3922 


5775.0952 


91 


285.8856 


6503.8974 


"sr 


269.7849 


5791.9445 


^ 


286.2783 


6521.7772 


86 


270.1776 


5808.8184 


286.6710 


6539.6801 


1 


270.5703 


5825.7168 


y 


287.0637 


6557.6114 


270.9630 


5842.6376 


5- 


287.4564 


6573.5651 


1 


271.3557 


5859.5871 


1 


287.8491 


6593.5431 


|. 


271.7484 


5876.5591 


1 


288.2418 


6611.5462 


^ 


272.1411 


5893.5549 




288.6345 


6629.5736 


1 


272.5338 


5910.5767 


92 


289.0272 


6647.6258 


i 


272.9265 


5927.6224 


1 


289.4199 


. 6665.7021 


87 


273.3192 


5944.6926 


J 


289.8125 


6683.8010 


X 


273.7119 


5961.7873 


1 


290.2053 


6701.9286 


■ . 


274.1046 


5978.9045 


5- 


290.5980 


6720.0787 


1 


274.4973 


5996.0504 


8 


290.9907 


6738.2530 


. . 


274.8900 


6013.2187 




291.3834 


6756.4525 


I 


275.2827 


6030.4108 


e 

T 


291.7661 


6774.6763 


f 


275.6754 


6047.6290 


93 


292.1688 


6792.9248 


i 


276.0681 


6064.8710 


J 


292.5615 


6811.1974 


88 


276.4608 


6082.1376 


i 


292.9542 


6829.4927 




276.8535 


6099.4287 


■| 


293.3469 


6847.8167 


277.2462 


6116.7422 


i 


293.7396 


6866.1631 




277.6389 


6134.0844 


-| 


294.1323 


6884.5338 


1 . 


278.0316 


6151.4491 


1 


294.5350 


6902;9296 


^ 


278.4243 


6169.8376 


1 


294.9177 


6921.3497 


f 


278.8170 


6186.2591 


94 


295.3104 


6939.7946 



HAND-BOOK OF LAND AND MARINE ENGINES. 531 

T A B li 'B — (Concluded) 
CONTAINING THE DIAM., CIRCUMFEKENCES, AND AREAS OF CIRCLES. 



DiAM. 


ClRCUM. 


Area. 


DiAM. 


CiRCUM. 


Area. 


Inch. 






Inch. 






i 


295.7031 


6958.2636 


i 


305.1279 


7408.8868 


i 


296.0958 


6976.7552 


i 


305.5206 


7427.9675 


1 


296.4885 


6995.2755 


f 


305.9133 


7447.0769 




296.8812 


7013.8183 




306.3060 


7466.2087 


-| 


297.2739 


7032.3853 


-| 


306.6987 


7485.3648 


1 


297.6666 


7050.9775 


1 


307.0914 


7504.5460 


1 


298.0593 


7069.5940 


|- 


307.4841 


7523.7515 


95 


298.4520 


7088.2352 


98 


307.8768 


7542.9818 


- 


298.8447 


7106.9005 


i 


308.2695 


7562.2362 




299.2374 


7125.5885 




308.6622 


7581.5132 




299.6301 


7144.3052 


1 


309.0549 


7600.8189 


: ■ 


300.0228 


7163.0443 


^ 


309.4476 


7620.1471 


1 


300.4155 


7181.8077 


1 


309.8403 


7639.4995 


1 


300.8082 


7200.5962 


1 


310.2330 


7658.8771 


i 


301.2009 


7219.4090 


1 


310.6257 


7678.2790 


96 


301.5936 


7238.2466 


99 


311.0184 


7697.7056 


i 


301.9863 


7257.1083 


.. 


311.4111 


7717.1563 




302.3790 


7275.9926 


. . 


311.8038 


7736.6297 


1 


302.7717 


7294.9056 




312.1965 


7756.1318 


^ 


303.1644 


7313.8411 


• . 


312.5892 


7775.6563 


1 


303.5571 


7332.8008 


^ 


312.9819 


7795.2051 


1 


303.9498 


7351.7857 


1 


313.3746 


7814.7790 


i 


304.3425 


7370.7949 


313.7673 


7834.3772 


97 


304.7352 


7389.8288 


100 


314.1600 


7854.0000 



For the Circumference of Larger Circles than those contained 
in the Tables, — Multiply the diameter by 3'1416. 

EXAMPLE. : 

Diam. in inches, 110 

3-1416 

345-5760 

For areas larger than those in the Tables, see page 489. 



5a2 



HAND-BOOK OF LAND AND MARINE ENGINES. 



TABLE 

OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS OP ALL 
NUMBERS FROM 1 TO 620. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


1 


1 


1 


1. 


1. 


2 


4 


8 


1.4142 136 


1.2599 21 


3 


9 


27 


1.7230 508 


1.4422 496 


4 


16 


64 


2. 


1.5874 Oil 


5 


25 


125 


2.2360 68 


1.7099 759 


6 


36 


216 


2.4494 897 


1.8171 206 


7 


49 


343 


2.6457 513 


1.9129 312 


8 


64 


512 


2.8284 271 


2. 


9 


81 


729 


3. 


2.0800 837 


10 


1 00 


1 000 


3.1622 777 


2.1544 347 


11 


1 21 


1 331 


3.3166 248 


2.2239 801 


12 


1 44 


1 728 


3.4641 016 


2.2894 286 


13 


1 69 


2 197 


3.6055 513 


2.3513 347 


14 


1 96 


2 744 


3.7416 574 


2.4101 422 


15 


2 25 


3 375 


3.8729 833 


2.4662 121 


16 


2 56 


4 096 


4. 


2.5198 421 


17 


2 89 


4 913 


4.1231 056 


2.5712 816 


18 


3 24 


5 832 


4.2426 407 


2.6207 414 


19 


3 61 


6 859 


4.3585 98.9 


2.6684 016 


20 


4 00 


8 000 


4.4721 36 


2.7144 177 


21 


4 41 


9 261 


4.5825 757 


2.7589 243 


22 


4 84 


10 648 


4.6904 158 


2.8020 393 


23 


5 29 


12 167 


4.7958 315 


2.8438 67 


24 


5 76 


13 824 


4.8989 795 


2.8844 991 


25 


6 25 


15 625 


5. 


2.9240 177 


26 


6 76 


17 576 


5.0990 195 


2.9224 96 


27 


7 29 


19 683 


5.1961 524 


3. 


28 


7 84 


21 952 


5.2915 026 


3.0365 889 


29 


8 41 


24 389 


5.3851 648 


3.0723 168 


30 


9 00 


27 000 


5.4772 256 


3.1072 325 


31 


9 61 


29 791 


5.5677 644 


3.1413 806 


32 


10 24 


32 768 


5.6568 542 


3.1748 021 


33 


10 89 


35 937 


5.7445 626 


3.2075 343 


34 


11 56 


39 304 


5.8309 519 


3.2396 118 


35 


12 25 


42 875 


5.9160 798 


3.2710 663 


36 


12 96 


46 656 


6. 


3.3019 272 


37 


13 69 


50 653 


6.0827 625 


3.3322 218 


38 


14 44 


54 872 


6.1644 14 


3.3619 754 


39 


15 21 


59 319 


6.2449 98 


3.3912 114 


40 


16 00 


64 000 


6.3245 553 


3.4199 519 


41 


16 81 


68 921 


6.4031 242 


3.4482 172 



HAND-BOOK OF LAND AND MAHINE ENGINES. 



533 



TABLE~( 

OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


42 


17 64 


74 088 


6.4807 407 


3.4760 266 


43 


18 49 


79 507 


6.5574 385 


3.5033 981 


44 


19 36 


85 184 


6.6332 496 


3.5303 483 


45 


20 25 


91 125 


6.7082 039 


3.5568 933 


46 


21 16 


97 336 


6.7823 3 


3.5830 479 


47 


22 09 


103 823 


6.8556 546 


3.6088 261 


48 


23 04 


110 592 


6.9282 032 


3.6342 411 


49 


24 01 


117 649 


7. 


3.6593 057 


50 


25 00 


125 000 


7.0710 678 


3.6840 314 


61 


26 01 


132 651 


7.1414 284 


3.7084 298 


52 


27 04 


140 608 


7.2111 026 


3.7325 111 


53 


28 09 


148 877 


7.2801 099 


3.7562 858 


54 


29 16 


157 464 


7.3484 692 


3.7797 631 


55 


30 25 


166 375 


7.4161 985 


3.8029 525 


56 


31 36 


175 616 


7.4833 148 


3.8258 624 


57 


32 49 


185 193 


7.5498 344 


3.8485 Oil 


58 


33 64 


195 112 


7.6157 731 


3.8708 766 


59 


34 81 


205 379 


7.6811 457 


8.8929 965 


60 


36 00 


216 000 


7.7459 667 


3.9148 676 


61 


37 21 


226 981 


7.8102 497 


3.9364 972 " 


62 


38 44 


238 328 


7.8740 079 


3.9578 915 


63 


39 69 


250 047 


7.9372 539 


3.9790 571 


64 


40 96 


262 144 


8. 


4. 


65 


42 25 


274 625 


8.0622 577 


4.0207 256 


66 


43 56 


287 496 


8.1240 384 


4.0412 401 


67 


44 89 


300 763 


8.1853 528 


4.0615 48 


68 


46 24 


314 432 


8.2462 113 


4.0816 551 


69 


47 61 


328 509 


8.3066 239 


4.1015 661 


70 


49 00 


343 000 


8.3666 003 


4.1212 853 


71 


50 41 


357 911 


8.4261 498 


4.1408 178 


72 


51 84 


373 248 


8.4852 814 


4.1601 676 


73 


53 29 


389 017 


8.5440 037 


4.1793 39 


74 


54 76 


405 224 


8.6023 253 


4.1983 364 


75 


56 25 


421 875 


8.6602 54 


4.2171 633 


76 


57 76 


438 976 


8.7177 979 


4.2358 236 


77 


59 29 


456 533 


8.7749 644 


4.2543 21 


78 


60 84 


474 552 


8.8317 609 


4.2726 586 


79 


62 41 


493 039 


8.8881 944 


4.2908 404 


80 


64 00 


612 000 


8.9442 719 


4.3088 695 


81 


65 61 


631 441 


9. 


4.3267 487 


82 


67 24 


651 368 


9.0553 851 


4.3444 815 


83 


68 89 


571 787 


9.1104 336 


4.3620 707 



534 HAND-BOOK OF LAND AND MARINE ENGINES. 

TAlBlj'Ei — iConHnued) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



1 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


84 


70 56 


592 704 


9.1651 514 


4.3795 191 


85 


72 25 


614 125 


9.2195 445 


4.3968 296 


86 


73 96 


636 056 


9.2736 185 


4.4140 049 


87 


75 69 


658 503 


9.3273 791 


4.4310 476 


88 


77 44 


681 472 


9.3808 315 


4.4479 602 


89 


79 21 


704 969 


9.4339 811 


4.4647 451 


90 


81 00 


729 000 


9.4868 33 


4.4814 047 


91 


82 81 


753 571 


9.5393 92 


4.4979 414 


92 


84 64 


778 688 


9.5916 63 


4.5143 574 


93 


86 49 


804 357 


9.6436 508 


4.5306 549 


94 


88 36 


830 584 


9.6953 597 


4.5468 359 


95 


90 25 


857 375 


9.7467 943 


4.5629 026 


96 


92 16 


884 736 


9.7979 59 


4.5788 57 


97 


94 09 


912 673 


9.8488 578 


4.5947 009 


98 


96 04 


941 192 


9.8994 949 


4.6104 363 


99 


98 01 


970 299 


9.&498 744 


4.6260 65 


100 


1 00 00 


1 000 000 


10. 


4.6415 888 


101 


1 02 01 


1 030 301 


10.0498 756 


4.6570 095 


102 


1 04 04 


1 061 208 


10.0995 049 


4.6723 287 


103 


1 06 09 


1 092 727 


10.1488 916 


4.6875 482 


104 


1 08 16 


1 124 864 


10.1980 39 


4.7026 694 


105 


1 10 25 


1 157 ^25 


10.2469 508 


4.7176 94 


106 . 


1 12 36 


1 191 016 


10.2956 301 


4.7326 235 


107 


1 14 49 


1 225 043 


10.3440 804 


4.7474 594 


108 


1 16 64 


1 259 712 


10.3923 048 


4.7622 032 


109 


1 18 81 


1 295 029 


10.4403 065 


4.7768 562 


110 


1 21 00 


1 331 000 


10.4880 885 


4.7914 199 


111 


1 23 21 


1 367 631 


10.5356 538 


4.8058 995 


112 


1 25 44 


1 404 928 


10.5830 052 


4.8202 845 


113 


1 27 69 


1 442 897 


10.6301 458 


4.8345 881 


114 


1 29 96 


1 481 544 


10.6770 783 


4.8488 076 


115 


1 32 25 


1 520 875 


10.7238 053 


4.8629 442 


116 


1 34 56 


1 560 896 


10.7703 296 


4.8769 99 


117 


1 36 89 


1 601 613 


10.8166 638 


4.8909 732 


118 


1 39 24 


1 643 032 


10.8627 805 


4.9048 681 


119 


1 41 61 


1 685 159 


10.9087 121 


4.9186 847 


120 


1 44 00 


1 728 000 


10.9544 512 


4.9324 242 


121 


1 46 41 


1 771 561 


11. 


4.9460 874 


122 


1 48 34 


1 815 848 


11.0453 61 


4.9596 757 


123 


1 51 29 


1 860 867 


11.0905 365 


4.9731 898 


124 


1 53 76 


1 906 624 


11.1355 287 


4.9866 31 


125 


1 56 25 


1 953 125 


11.1803 399 


5. 



HAND-BOOK OF LA^^D AXD MARINE ENGINES. 



535 



TABLE — (Continued) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


126 


1 58 76 


2 000 376 


11.2249 722 


5.0132 979 


127 


1 61 29 


2 048 383 


11.2694 277 


5.0265 257 


128 


1 63 84 


2 097 152 


11.3137 085 


5.0396 842 


129 


1 66 41 


2 146 689 


11.3578 167 


5.0527 743 


130 


1 69 00 


2 197 000 


11.4017 543 


5.0657 97 


131 


1 71 61 


2 248 091 


11.4455 231 


5.0787 531 


132 


1 74 24 


2 299 968 


11.4891 253 


5.0916 434 


133 


1 76 89 


2 352 637 


11.5325 626 


5.1044 687 


134 


1 79 56 


2 406 104 


11.5758 369 


5.1172 299 


135 


1 82 25 


2 460 375 


11.6189 5 


5.1299 278 


136 


1 84 96 


2 515 456 


11.6619 038 


5.1425 632 


137 


1 87 69 


2 571 353 


11.7046 999 


5.1551 367 


138 


1 90 44 


2 628 072 


11.7473 401 


5.1676 493 


139 


1 93 21 


2 685 619 


11.7898 261 


5.1801 015 


140 


1 96 00 


2 744 000 


11.8321 596 


5.1924 941 


141 


1 98 81 


2 803 221 


11.8743 421 


5.2048 279 


142 


2 01 64 


2 863 288 


11.9163 753 


5.2171 034 


143 


2 04 49 


2 924 207 


11.9582 607 


5.2293 215 


144 


2 07 36 


2 985 984 


12. 


5,2414 828 


145 


2 10 25 


3 048 625 


12.0415 946 


5.2535 879 


146 


2 13 16 


3 112 136 


12.0830 46 


5.2656 374 


147 


2 16 09 


3 176 523 


12.1243 557 


5.2776 321 


148 


2 19 04 


3 241 792 


12.1655 251 


5.2895 725 


149 


2 22 01 


3 307 949 


12.2065 556 


5.3014 592 


150 


2 25 00 


3 375 000 


12.2474 487 


5.3132 928 


151 


2 28 01 


3 442 951 


12.2882 057 


5.3250 74 


152 


2 31 04 


3 511 008 


12.3288 28 


5.3368 033 


153 


2 34 09 


3 581 577 


12.3693 169 


5.3484 812 


154 


2 37 16 


3 652 264 


12.4096 736 


5.3601 084 


155 


2 40 25 


3 723 875 


12.4498 996 


5.3716 854 


156 


2 43 36 


3 796 416 


12.4899 96 


5.3832 126 


157 


2 46 49 


3 869 893 


12.5299 641 


5.3946 907 


158 


2 49 64 


3 944 312 


12.5698 051 


5.4061 202 


159 


2 52 81 


4 019 679 


12.6095 202 


5.4175 015 


160 


2 56 00 


4 096 000 


12.6491 106 


5.4288 352 


161 


2 59 21 


4 173 281 


12.6885 775 


5.4401 218 


162 


2 62 44 


4 251 528 


12.7279 221 


5.4513 618 


163 


2 65 69 


4 330 747 


12.7671 453 


5.4625 556 


164 


2 68 96 


4 410 944 


12.8062 485 


5.4737 037 


165 


2 72 25 


4 492 125 


12.8452 326 


5.4848 066 


166 


2 75 56 


4 574 296 


12.8840 987 


5.4958 647 


167 


2 78 89 


4 657 463 


12.9228 48 


5.5068 784 



536 



HAKD-BOOK OF LAND AND MARINE ENGINES. 



TAB I^IB^ — (Continued) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


168 


2 82 24 


4 741 632 


12.9614 814 


5.5178 484 


169 


2 85 61 


4 826 809 


13. 


5.5287 748 


170 


2 89 00 


4 913 000 


13.0384 048 


5.5396 583 


171 


2 92 41 


5 000 211 


13.0766 968 


5.5504 991 


172 


2 95 84 


5 088 448 


13.1148 77 


5.5612 978 


173 


2 99 29 


5 177 717 


13.1529 464 


5.5720 546 


174 


3 02 76 


5 268 024 


13.1909 06 


5.5827 702 


175 


3 06 25 


5 359 375 


13.2287 566 


5.5934 447 


176 


3 09 76 


5 451 776 


13.2664 992 


5.6040 787 


177 


3 13 29 


5 545 233 


13.3041 347 


5.6146 724 


178 


3 16 84 


5 639 752 


13.3416 641 


5.6252 263 


179 


3 20 41 


5 735 339 


13.3790 882 


5.6357 408 


180 


3 24 00 


5 832-000 


13.4164 079 


5.6462 162 


181 


3 27 61 


6 929 741 


13.4536 24 


5.6566 528 


182 


3 31 24 


6 028 568 


13.4907 376 


5.6670 511 


183 


3 34 89 


6 128 487 


13.5277 493 


5.6774 114 


184 


3 38 56 


6 229 504 


13.5646 6 


5.6877 34 


185 


3 42 25 


6 331 625 


13.6014 705 


. 5.6980 192 


186 


3 45 96 


6 434 856 


13.6381 817 


5.7082 675 


187 


3 49 69 


6 539 203 


13.6747 943 


5.7184 791 


18*8 


3 53 44 


6 644 672 


13.7113 092 


5.7286 543 


189 


3 57 21 


6 751 269 


13.7477 271 


5.7387 936 


190 


3 61 00 


6 859 000 


13.7840 488 


5.7488 971 


191 


3 64 81 


6 967 871 


13.8202 75 


5.7589 652 


192 


3 68 64 


7 077 888 


13.8564 065 


5.7689 982 


193 


3 72 49 


7 189 057 


13.8924 4 


5.7789 966 


194 


3 76 36 


7 301 384 


13.9283 883 


5.7889 604 


. 195 


3 80 25 


7 414 875 


13.9642 4 


6.7988 9 


-196 


3 84 16 


7 529 536 


14. 


5.8087 857 


197 


3 88 09 


7 645 373 


14.0356 688 


5.8186 479 


198 


3 92 04 


7 762 392 


14.0712 473 


5,8284 867 


199 


3 96 01 


7 880 599 


14.1067 36 


5.8382 725 


200 


4 00 00 


8 000 000 


14.1421 356 


5.8480 355 


201 


4 04 01 


8 120 601 


14.1774 469 


5.8577 66 


202 


4 08 04 


8 242 408 


14.2126 704 


5.8674 673 


203 


4 12 09 


8 365 427 


14.2478 068 


6.8771 307 


204 


4 16 16 


8 489 664 


14.2828 569 


5.8867 653 


205 


4 20 25 


8 615 125 


14.3178 211 


5.8963 685 


206 


4 24 36 


8 741 816 


14.3527 001 


6.9059 406 


207 


4 28 49 


8 869 743 


14.3874 946 


5.9154 817 


208 


4 32 64 


8 998 912 


14.4222 051 


5.9249 921 


209 


4 36 81 


9 129 329 


14.4568 323 


5.9344 721 



HAND-BOOK OF LAND AND MARINE ENGINES. 



537 



TABLE — {Continued) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


210 


4 41 00 


9 261 000 


14.4913 767 


5.9439 22 


211 


4 45 21 


9 393 931 


14.5258 39 


5.9533 418 


212 


4 49 44 


9 528 128 


14.5602 198 


5.9627 32 


213 


4 53 69 


9 663 597 


14.5945 195 


5.9720 926 


214 


4 57 96 


9 800 344 


14.6287 388 


5.9814 24 


215 


4 62 25 


9 938 375 


14.6628 783 


5.9907 264 


216 


4 m 56 


10 077 696 


14.6969 385 


6. 


217 


4 70 89 


10 218 313 


14.7309 199 


6.0092 45 


218 


4 75 24 


10 360 232 


14.7648 231 


6.0184 617 


219 


4 79 61 


10 503 459 


14.7986 486 


6.0276 502 


220 


4 84 00 


10 648 000 


14.8323 97 


6.0368 107 


221 


4 88 41 


10 793 861 


14.8660 687 


6.0459 435 


222 


4 92 84 


10 941 048 


14.8996 644 


6.0550 489 


223 


4 97 29 


11 089 567 


14.9331 845 


6.0641 27 


224 


5 01 76 


11 239 424 


14.9666 295 


6.0731 779 


225 


5 06 25 


11 390 625 


15. 


6.0822 02 


226 


5 10 76 


11 543 176 


15.0332 964 


6.0911 994 


227 


5 15 29 


11 697 083 


15.0665 192 


6.1001 702 


228 


5 19 84 


11 852 352 


15.0996 689 


6.1091 147 


229 


5 24 41 


12 008 989 


15.1327 46 


6.1180 332 


230 


5 29 00 


12 167 000 


15.1657 509 


6.1269 257 


231 


5 33 61 


12 326 391 


15.1986 842 


6.1357 924 


232 


5 38 24 


12 487 168 


15.2315 462 


6.1446 337 


233 


5 42 89 


12 649 337 


15.2643 375 


6.1534 495 


234 


5 47 56 


12 812 904 


15.2970 585 


6.1622 401 


235 


5 52 25 


12 977 875 


15.3297 097 


6.1710 058 


236 


5 56 96 


13 144 256 


15.3622 915 


6.1797 466 


237 


5 61 69 


13 312 053 


15.3948 043 


6.1884 628 


238 


5 66 44 


13 481 272 


15.4272 486 


6.1971 544 


239 


5 71 21 


13 651 919 


15.4596 248 


6.2058 218 


240 


6 76 00 


13 824 000 


15.4919 334 


6.2144 65 


241 


5 80 81 


13 997 521 


15.5241 747 


6.2230 843 


242 


5 85 64 


14 172 488 


15.5563 492 


6.2316 797 


243 


5 90 49 


14 348 907 


15.5884 573 


6.2402 515 


244 


5 95 36 


14 526 784 


15.6204 994 


6.2487 998 


245 


6 00 25 


14 706 125 


15.6524 758 


6.2573 248 


246 


6 05 16 


14 886 936 


15.6843 871 


6.2658 266 


247 


6 10 09 


15 069 223 


15.7162 336 


6.2743 054 


248 


6 15 04 


15 252 992 


15.7480 157 


6.2827 613 


249 


6 20 01 


15 438 249 


15.7797 338 


6.2911 946 


250 


6 25 00 


15 625 000 


15.8113 883 


6.2996 053 


251 


6 30 01 


15 813 251 


15.8429 795 


6.3079 935 



538 • HAND-BOOK OF LAITD AND MAEINE ENGINES. 



TAlBLi^ — iOontiniied) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


252 


6 35 04 


16 003 008 


15.8745 079 


6.3163 696 


253 


6 40 09 


16 194 277 


15.9059 737 


6.3247 035 


254 


6 45 16 


16 387 064 


15.9373 775 


6.3330 256 


255 


6 50 25 


16 581 375 


15.9687 194 


6.3413 257 


256 


6 55 36 


16 777 216 


16. 


6.3496 042 


257 


6 60 49 


16 974 593 


16.0312 195 


6.3578 611 


258 


6 65 64 


17 173 512 


16.0623 784 


6.3660 968 


259 


6 70 81 


17 373 979 


16.0934 769 


6.3743 111 


260 


6 76 00 


17 576 000 


16.1245 155 


6.3825 043 


261 


6 81 21 


17 779 581 


16.1554 944 


6.3906 765 


262 


6 86 44 


17 984 728 


16.1864 141 


6.3988 279 


263 


6 91 69 


18 191 447 


16.2172 747 


6.4069 585 


264 


6 96 96 


18 399 744 


16.2480 768 


6.4150 687 


265 


7 02 25 


18 609 625 


16.2788 206 


6.4231 583 


266 


7 07 56 


18 821 096 


16.3095 064 


6.4312 276 


267 


7 12 89 


19 034 163 


16.3401 346 


6.4392 767 


268 


7 18 24 


19 248 832 


16.3707 055 


6.4473 057 


269 


7 23 61 


19 465 109 


16.4012 195 


6.4553 148 


270 


7 29 00 


19 683 000 


16.4316 767 


6.4633 041 


271 


7 34 41 


19 902 511 


16.4620 776 


6.4712 736 


272 


7 39 84 


20 123 648 


16.4924 225 


6.4792 236 


273 


7 45 29 


20 346 417 


16.5227 116 


6.4871 641 


274 


7 50 76 


20 570 824 


16.5529 454 


6.4950 653 


275 


7 56 25 


20 796 875 


16.5831 24 


6.5029 572 


276 


7 61 76 


21 024 576 


16.6132 477 


6.5108 3 


277 


7 67 29 


21 253 933 


16.6433 17 


6.6186 839 


278 


7 72 84 


21 484 952 


16.6783 32 


6.5265 189 


279 


7 78 41 


21 717 639 


16.7032 931 


6.5343 361 


280 


7 84 00 


21 952 000 


16.7332 005 


6.5421 326 


281 


7 89 61 


22 188 041 


16.7630 546 


6.6499 116 


282 


7 95 24 


22 425 768 


16.7928 556 


«.6576 722 


' 283 


8 00 89 


22 665 187 


16.8226 038 


6.6654 144 


284 


8 06 56 


22 906 304 


16.8522 995 


6.5731 385 


• 285 


8 12 25 


23 149 125 


16.8819 43 


6.6808 443 


286 


8 17 96 


23 393 656 


16.9115 345 


6.6885 323 


287 


8 23 69 


23 639 903 


16.9410 743 


6.6962 023 


288 


8 29 44 


23 887 872 


16.9705 627 


6.6038 645 


289 


8 35 21 


24 137 569 


17. 


6.6114 89 


290 


8 41 00 


24 389 000 


17.0293 864 


6.6191 06 


291 


8 46 81 


24 642 171 


17.0587 221 


6.6267 064 


292 


8 52 64 


24 897 088 


17.0880 075 


6.6342 874 


293 


8 58 49 


25 153 757 


17.1172 428 


6.6418 522 



HAND-BOOK OF LAND AND MARINE ENGINES. 539 



T A B L E — ( Continued) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


294 


8 64 36 


25 412 184 


17.1464 282 


6.6493 998 


295 


8 70 25 


25 672 375 


17.1755 64 


6.6569 302 


296 


8 76 16 


25 934 336 


17.2046 505 


6.6644 437 


297 


8 82 09 


26 198 073 


17.2336 879 


6.6719 403 


298 


8 88 04 


26 463 592 


17.2626 765 


6.6794 2 


299 


8 94 01 


26 730 899 


17.2916 165 


6.6868 831 


300 


9 00 00 


27 000 000 


17.3205 081 


6.6943 295 


301 


9 06 01 


27 270 901 


17.3493 516 


6.7017 593 


302 


9 12 04 


27 543 608 


17.3781" 472 


6.7091 729 


303 


9 18 09 


27 818 127 


17.4068 952 


6.7165 7 


304 


9 24 16 


28 094 464 


17.4355 958 


6.7239 508 


305 


9 30 25 


28 372 625 


17.4642 492 


6.7313 155 


306 


9 36 36 


28 652 616 


17.4928 557 


6.7386 641 


307 


9 42 49 


28 934 443 


17.5214 155 


6.7459 967 


308 


9 48 64 


29 218 112 


17.5499 288 


6.7533 134 


309 


9 54 81 


29 503 609 


17.5783 958 


6.7606 143 


310 


9 61 00 


29 791 000 


17.6068 169 


6.7678 995 


311 


9 67 21 


30 080 231 


17.6151 921 


6.7751 69 


312 


9 73 44 


30 371 328 


17.6635 217 


6.7824 229 


313 


9 79 69 


30 664 297 


17.6918 06 


6.7896 613 


314 


9 85 96 


30 959 144 


17.7200 451 


6.7968 844 


315 


9 92 25 


31 255 875 


17.7482 393 


6.8040 921 


316 


9 98 56 


31 554 496 


17.7763 888 


6.8112 -847 


317 


10 04 89 


31 855 013 


17.8044 938 


6.8184 62 


318 


10 11 24 


32 157 432 


17.8325 545 


6.8256 242 


319 


10 17 61 


3^" 461 759 


17.8605 711 


6.8327 714 


320 


10 24 00 


32 768 000 


17.8885 438 


6.8399 037 


321 


10 30 41 


33 076 161 


17.9164 729 


6.8470 213 


322 


10 36 84 


33 386 248 


17.9443 584 


6.8541 24 


323 


10 43 29 


33 698 267 


17.9722 008 


6.8612 12 


324 


10 49 76 


34 012 224 


18. 


6.8682 855 


325 


10 56 25 


34 328 125 


18.0277 564 


6.8753 433 


326 


10 62 76 


34 645 976 


18.0554 701 


6.8823 888 


327 


10 69 29 


34 965 783 


18.0831 413 


6.8894 188 


328 


10 75 84 


35 287 552 


18.1107 703 


6.8964 345 


329 


10 82 41 


35 611 289 


18.1383 571 


6.9034 359 


330 


10 89 00 


35 937 000 


18.1659 021 


6.9104 232 


331 


10 95 61 


36 264 691 


18.1934 054 


6.9173 964 


332 


11 02 24 


36 594 368 


18.2208 672 


6.9243 556 


333 


11 08 89 


36 926 037 


18.2482 876 


6.9313 088 


334 


11 15 56 


37 259 704 


18.2756 669 


6.9382 321 


335 


11 22 25 


37 595 375 


18.3030 052 


6.9451 496 



540 



HAND-BOOK OF LAND AND MARINE ENGINES. 



T A B L. E — ( Continued) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


336 


11 28 96 


37 933 056 


18.3303 028 


6.9520 533 


337 


11 35 69 


38 272 753 


18.3575 598 


6.9589 434 


338 


11 42 44 


38 614 472 


18.3847 763 


6.9658 198 


339 


11 49 21 


38 958 219 


18.4119 526 


6.9726 826 


340 


11 56 00 


39 304 000 


18.4390 889 


6.9795 321 


341 


11 62 81 


39 651 821 


18.4661 853 


6.9863 681 


342 


11 69 64 


40 001 688 


18.4932 42 


6.9931 906 


343 


11 76 49 


40 353 607 


18.5202 592 


7. 


344 


11 83 36 


40 707 584 


18.5472 37 


7.0067 962 


345 


11 90 25 


41 063 625 


18.5741 756 


7.0135 791 


346 


11 97 16 


41 421 736 


18.6010 752 


7.0203 49 


347 


12 04 09 


41 781 923 


18.6279 36 


7.0271 058 


348 


12 11 04 


42 144 192 


18.6547 581 


7.0338 497 


349 


12 18 01 


42 508 549 


18.6815 417 


7.0405 806 


350 


12 25 00 


42 875 000 


18.7082 869 


7.0472 987 


351 


12 32 01 


43 243 551 


18.7349 94 


7.0540 041 


352 


12 39 04 


43 614 208 


18.7616 63 


7.0606 967 


353 


12 46 09 


43 986 977 


18.7882 942 


7.0673 767 


354 


12 53 16 


44 361 864 


18.8148 877 


7.0740 44 


355 


12 60 25 


44 738 875 


18.8414 437 


7.0806 988 


356 


12 67 36 


45 118 016 


18.8679 623 


7.0873 411 


357 


12 74 49 


45 499 293 


18.8944 436 


7.0939 709 


358 


12 81 64 


45 882 712 


18.9208 879 


7.1005 885 


359 


12 88 81 


46 268 279 


18.9472 953 


7.1071 937 


360 


12 96 00 


46 656 000 


18.9736 66 


7.1137 866 


361 


13 03 21 


47 045 831 


19. 


7.1203 674 


362 


13 10 44 


47 437 928 


19.0262 976 


7.1269 36 


363 


13 17 69 


47 832 147 


19.0525 589 


7.1334 925 


364 


13 24 96 


48 228 544 


19.0787 84 


7.1400 37 


365 


13 32 25 


48 627 125 


19.1049 732 


7.1465 695 


366 


13 39 56 


49 027 896 


19.1311 265 


7.1530 901 


367 


13 46 89 


49 430 863 


19.1572 441 


7.1595 988 


368 


13 54 24 


49 836 032 


19.1833 261 


7.1660 957 


369 


13 61 61 


50 243 409 


19.2093 727 


7.1725 809 


370 


13 69 00 


50 653 000 


19.2353 841 


7.1790 544 


371 


13 76 41 


51 064 811 


19.2613 603 


7.1855 162 


372 


13 83 84 


51 478 848 


19.2873 015 


7.1919 663 


373 


13 91 29 


51 895 117 


19.3132 079 


7.1984 05 


374 


13 98 76 


52 313 624 


19.3390 796 


7.2048 322 


375 


14 06 25 


52 734 375 


19.3649 167 


7.2112 479 


376 


14 13 76 


53 157 376 


19.3907 194 


7.2176 522 


377 


14 21 29 


53 582 633 


19.4164 878 


7.2240 45 



HAND-BOOK OF LAND AND MARINE ENGINES. 541 



TABLE- (Continued) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


378 


14 28 84 


54 010 152 


19.4422 221 


7.2304 268 


379 


14 36 41 


54 439 939 


19.4679 223 


7.2367 972 


380 


14 44 00 


54 872 000 


19.4935 887 


7.2431 565 


381 


14 51 61 


55 306 341 


19.5192 213 


7.2495 045 


■382 


14 59 24 


55 742 968 


19.5448 203 


7.2558 415 


383 


14 66 89 


56 181 887 


19.5703 858 


7.2621 675 


384 


14 74 56 


56 623 104 


19.5959 179 


7.2684 824 


385 


14 82 25 


57 066 625 


19.6214 169 


7.2747 864 


386 


14 89 96 


57 512 456 


19.6468 827 


7.2810 794 


387 


14 97 69 


57 960 603 


19.6723 156 


7.2873 617 


388 


15 05 44 


58 411 072 


19.6977 156 


7.2936 33 


389 


15 13 21 


58 863 869 


19.7230 829 


7.2998 936 


390 


15 21 00 


59 319 000 


19.7484 177 


7.3061 436 


391 


15 28 81 


59 776 471 


19.7737 199 


7.3123 828 


392 


15 36 64 


60 236 288 


19.7989 899 


7.3186 114 


393 


15 44 49 


60 698 457 


19.8242 276 


7.3248 295 


394 


15 52 36 


61 162 984 


19.8494 332 


7.3310 369 


395 


15 60 25 


61 629 875 


19.8746 069 


7.3372 339 


396 


15 68 16 


62 099 136 


19.8997 487 


7.3434 205 


397 


15 76 09 


62 570 773 


19.9248 588 


7.3495 966 


398 


15 84 04 


63 044 792 


19.9499 373 


7.3557 624 


399 


15 92 01 


63 521 199 


19.9749 844 


7.3619 178 


400 


16 00 00 


64 000 000 


20. 


7.3680 63 


401 


16 08 01 


64 481 201 


20.0249 844 


7.3741 979 


402 


16 16 04 


64 964 808 


20.0499 377 


7.3803 227 


403 


16 24 09 


65 450 827 


20.0748 599 


7.3864 373 


404 


16 32 16 


65 939 264 


20.0997 512 


7.3925 418 


405 


16 40 25 


m 430 125 


20.1246 118 


7.3986 363 


406 


16 48 36 


66 923 416 


20.1494 417 


7.4047 206 


407 


16 56 49 


67 419 143 


20.1742 41 , 


7.4107 95 


408 


16 64 64 


67 917 312 


20.1990 099 


7.4168 595 


409 


16 72 81 


68 417 929 


20.2237 484 


7.4229 142 


410 


16 81 00 


68 921 000 


20.2484 567 


7.4289 589 


411 


16 89 21 


69 426 531 


20.2731 349 


7.4349 938 


412 


16 97 44 


69 934 528 


20.2977 831 


7.4410 189 


413 


17 05 69 


70 444 997 


20.3224 014 


7.4470 342 


414 


17 13 96 


70 957 944 


20.3469 899 


7.4530 399 


415 


17 22 25 


71 473 375 


20.3715 488 


7.4590 359 


416 


17 30 56 


71 991 296 


20.3960 781 


7.4650 223 


417 


17 38 89 


72 511 713 


20.4205 779 


7.4709 991 


418 


J7 47 24 


73 034 632 


20.4450 483 


7,4769 664 


419 


17 55 61 


73 560 059 


20.4694 895 


7.4829 242 



542 



HAND-BOOK OF LAND AND MARINE ENGINES. 



T A B L E — ( Continued) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


420 


17 64 00 


74 088 000 


20.4939 015 


7.4888 724 


421 


17 72 41 


74 618 461 


20.5182 845 


7.4948 113 


422 


17 80 84 


75 151 448 


20.5426 386 


7.5007 406 


423 


17 89 29 


75 686 967 


20.5669 638 


.7.5066 607 


424 


17 97 76 


76 225 024 


20.5912 603 


7.5125 715 


425 


18 06 25 


76 765 625 


20.6155 281 


7.5184 73 


426 


18 14 76 


77 308 776 


20.6397 674 


7.5243 652 


427 


18 23 29 


77 854 483 


20.6639 783 


7.5302 482 


428 


18 31 84 


78 402 752 


20.6881 609 


7.5361 221 


429 


18 40 41 


78 953 589 


20.7123 152 


7.5419 867 


430 


18 49 00 


79 507 000 


20.7364 414 


7.5478 423 


431 


18 57 61 


80 062 991 


20.7605 395 


7.5536 888 


432 


18 66 24 


80 621 568 


20.7846 097 


7.5595 263 


433 


18 74 89 


81 182 737 


20.8086 52 


7.5653 548 


434 


18 83 56 


81 746 504 


20.8326 667 


7.5711 743 


435 


18 92 25 


82 312 875 


20.8566 536 


7.5769 849 


436 


19 00 96 


82 881 856 


20.8806 13 


7.5827 865 


437 


19 09 69 


83 453 453 


20.9045 45 


7.5885 7-93 


438 


19 18 44 


84 027 672 


20.9284 495 


7.5943 633 


439 


19 27 21 


84 604 519 


20.9523 268 


7.6001 385 


440 


19 36 00 


85 184 000 


20.9761 77 


7.6059 049 


441 


19 44 81 


85 766 121 


21. 


7.6116 626 


442 


19 53 64 


86 350 888 


21.0237 96 


7.6174 116 


443 


19 62 49 


86 938 307 


21.0475 652 


7.6231 519 


444 


19 71 36 


87 528 384 


21.0713 075 


7.6288 837 


445 


19 80 25 


88 121 125 


21.0950 231 


7.6346 067 


446 


19 89 16 


88 716 536 


21.1187 121 


7.6403 213 


447 


19 98 09 


89 314 623 


21.1423 745 


7.6460 272 


448 


20 07 04 


89 915 392 


21.1660 105 


7.6517 247 


449 


20 16 01 


90 518 849 


21.1896 201 


7.6574 138 


450 


20 25 00 


91 125 000 


21.2132 034 


7.6630 943 


451 


20 34 01 


91 733 851 


21.2367 606 


7.6687 665 


452 


20 43 04 


92 345 408 


21.2602 916 


7.6744 303 


453 


20 52 09 


92 959 677 


21.2837 967 


7.6800 857 


454 


20 61 16 


93 576 664 


21.3072 758 


7.6857 328 


455 


20 70 25 


94 196 375 


21.3307 29 


7.6913 717 


456 


20 79 36 


94 818 816 


21.3541 565 


7.6970 023 


457 


20 88 49 


95 443 993 


21.3775 583 


7.7026 246 


458 


20 97 64 


96 071 91^ 


21.4009 346 


7.7082 388 


459 


21 06 81 


96 702 579 


21.4242 853 


7.7138 448 


460 


21 16 00 


97 336 000 


21.4476 106 


7.7194 426 


461 


21 25 21 


97 972 181 


21.4709 106 


7.7250 325 



HAND-BOOK OF LAND AND MARINE ENGINES. 513 



TABLE — (Contiwued) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


462 


21 34 44 


98 611 128 


21.4941 853 


7.7306 141 


463 


21 43 69 


99 252 847 


21.5174 348 


7.7361 877 


464 


21 52 96 


99 897 344 


21.5406 592 


7.7417 532 


465 


21 62 25 


100 544 625 


21.5638 587 


7.7473 109 


466 


21 71 56 


101 194 696 


21.5870 331 


7.7528 606 


467 


21 80 89 


101 847 563 


21.6101 828 


7.7584 023 


468 


21 90 24 


102 503 232 


21.6333 077 


7.7639 361 


469 


21 99 61 


103 161 709 


21.6564 078 


7.7694 62 


470 


22 09 00 


103 823 000 


21.6794 834 


7.7749 801 


471 


22 18 41 


104 487 111 


21.7025 344 


7.7804 904 


472 


22 27 84 


105 154 048 


21.7255 61 


7.7859 928 


473 


22 37 29 


105 823 817 


21.7485 632 


7.7914 875 


474 


22 46 76 


106 496 424 


21.7715 411 


7.7969 745 


475 


22 56 25 


107 171 875 


21.7944 947 


7.8024 538 


476 


22 65 76 


107 850 176 


21.8174 242 


7.8079 254 


477 


22 75 29 


108 531 333 


21.8403 297 


7.8133 892 


478 


22 84 84 


109 215 352 


21.8632 111 


7.8188 456 


479 


22 94 41 


109 902 239 


21.8860 686 


7.8242 942 


480 


23 04 00 


no 592 000 


21.9089 023 


7.8297 353 


481 


23 13 61 


111 284 641 


21.9317 122 


7.8351 688 


482 


23 23 24 


111 980 168 


21.9544 984 


7.8405 949 


483 


23 32 89 


112 678 587 


21.9772 61 


7.8460 134 


484 


23 42 56 


113 379 904 


22. 


7.8514 244 


485 


23 52 25 


114 084 125 


22.0227 155 


7.8568 281 


486 


23 61 96 


114 791 256 


22.0454 077 


7.8622 242 


487 


23 71 69 


115 501 303 


22.0680 765 


7.8676 13 


488 


23 81 44 


116 214 272 


22.0907 22 


7.8729 944 


489 


23 91 21 


116 930 169 


22.1133 444 


7.8783 684 


490 


24 01 00 


117 649 000 


22.1359 436 


7.8837 352 


491 


24 10 81 


118 370 771 


22.1585 198 


7.8890 946 


492 


24 20 64 


119 095 488 


22.1810 73 


7-8944 468 


493 


24 30 49 


119 823 157 


22.2036 033 


7.8997 917 


494 


24 40 36 


120 553 784 


22.2261 108 


7.9051 294 


495 


24 50 25 


121 287 375 


22.2485 955 


7.9104 599 


496 


24 60 16 


122 023 936 


22.2710 575 


7.9157 832 


497 


24 70 09 


122 763 473 


22,2934 968 


7.9210 994 


498 


24 80 04 


123 505 992 


22.3159 136 


7.9264 085 


499 


24 90 01 


124 251 499 


22.3383 079 


7.9317 104 


500 


25 00 00 


125 000 000 


22.3606 798 


7.9370 053 


501 


25 10 01 


125 751 501 


22.3830 293 


7.9422 931 


502 


25 20 04 


126 506 008 


22.4053 565 


7.9475 739 


503 


25 30 09 


127 263 527 


22.4276 615 


7.9528 477 



544 



HAND-BOOK OF LAND AND MARINE ENGINES. 



TABLE — (Continued) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


504 


25 40 16 


128 024 064 


22.4499 443 


7.9581 144 


505 


25 50 25 


128 787 625 


22.4722 051 


7.9633 743 


506 


25 60 36 


129 554 246 


22.4944 438 


7.9686 271 


507 


25 70 49 


130 323 843 


22.5166 605 


7.9738 731 


508 


25.80 64 


131 096 512 


22.5388 553 


7.9791 122 


509 


25 90 81 


131 872 229 


22.5610 283 


7.9843 444 


510 


26 01 00 ^ 


132 651 000 


22.5831 796 


7.9895 697 


511 


26 11 21 


133 432 831 


22.6053 091 


7.9947 883 


512 


26 21 44 


134 217 728 


22.6274 17 


8. 


513 


26 31 69 


135 005 697 


22.6495 033 


8.0052 049 


514 


26 41 96 


135 796 744 


22.6715 681 


8.0104 032 


515 


26 52 25 


136 590 875 


22.6936 114 


8.0155 946 


516 


26 62 56 


137 388 096 


22.7156 334 


8.0207 794 


517 


26 72 89 


138 188 413 


22.7376 340 


8.0259 574 


518 


26 83 24 


138' 991 832 


22.7596 134 


8.0311 287 


519 


26 93 61 


139 798 359 


22.7815 715 


8.0362 935 


520 


27 04 00 


140 608 000 


22.8035 085 


8.0414 515 


521 


27 14 41 


141 420 761 


22.8254 244 


8.0466 03 


522 


27 24 84 


142 236 648 


22.8473 193 


8.0517 479 


523 


27 35 29 


143 055 667 


22.8691 933 


8.0568 862 


524 


27 45 76 


143 877 824 


22.8910 463 


8.0620 18 


525 


27 56 25 


144 703 125 


22.9128 785 


8.0671 432 


526 


27 66 76 


145 531 576 


22.9346 899 


8.0722 62 


527 


27 77 29 


146 363 183 


22.9564 806 


8.0773 743 


528 


27 87 84 


147 197 952 


22.9782 506 


8.0824 8 


529 


27 98 41 


148 035 889 


23. 


8.0875 794 


530 


28 09 00 


148 877 000 


23.0217 289 


8.0926 723 


531 


28 19 61 


149 721 291 


23.0434 372 


8.0977 589 


532 


28 30 24 


150 568 768 


23.0651 252 


8.1028 39 


533 


28 40 89 


151 419 437 


23.0867 928 


8.1079 128 


534 


28 51 56 


152 273 304 


23.1084 4 


8.1129 803 


535 


28 62 25 


153 130 375 


23.1300 67 


8.1180 414 


536 


28 72 96 


153 990 656 


23.1516 738 


8.1230 962 


537 


28 83 69 


154 854 153 


23.1732 605 


8.1281 447 


538 


28 94 44 


155 720 872 


23.1948 37 


8.1331 87 


539 


29 05 21 


156 590 819 


23.2163 735 


8.1382 23 


540 


29 16 00 


157 464 000 


23.2379 001 


8.1432 529 


541 


29 26 81 


158 340 421 


23.2594 067 


8.1482 765 


542 


29 37 64 


159 220 088 


23.2808 935 


8.1532 939 


543 


29 48 49 


160 103 007 


23.3023 604 


8.1583 051 


544 


29 59 36 


160 969 184 


23.3238 076 


8.1633 102 


545 


29 70 25 


161 878 625 


23.3452 351 


8.1683 092 



HAND-BOOK OF LAND AND MARINE ENGINES. 



545 



T A B L E — ( Continued) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. 


Square Root. 


Cube Root. 


546 


29 81 16 


162 771 336 


23.3666 429 


8.1733 02 


547 


29 92 09 


163 667 323 


23.3880 311 


8.1782 888 


548 


30 03 04 


164 566 592 


23.4093 998 


8.1832 695 


549 


30 14 01 


165 469 149 


23.4307 49 


8.1882 441 


550 


30 25 00 


166 375 000 


23.4520 788 


8.1932 127 


551 


30 36 01 


167 284 151 


23.4733 892 


8.1981 753 


552 


30 47 04 


168 196 608 


23.4946 802 


8.2031 319 


553 


30 58 09 


169 112 377 


23.5159 52 


8.2080 825 


554 


30 69 16 


170 031 464 


23.5372 046 


8.2130 271 


555 


30 80 25 


170 953 875 


23.5584 38 


8.2179 657 


556 


30 91 36 


171 879 616 


23.5796 522 


8.2228 985 


557 


31 02 49 


172 808 693 


23.6008 474 


8.2278 254 


558 


31 13 64 


173 741 112 


23.6220 236 


8.2827 463 


559 


31 24 81 


174 676 879 


23.6431 808 


8.2376 614 


560 


31 36 00 


175 616 000 


23.6643 191 


8.2425 706 


561 


31 47 21 


176 558 481 


23.6854 386 


8.2474 74 


562 


31 58 44 


177 504 328 


23.7065 392 


8.2523 715 


563 


31 69 69 


178 453 547 


23.7276 21 


8.2572 635 


564 


31 80 96 


179 406 144 


23.7486 842 


8.2621 492 


565 


31 92 25 


180 362 125 


23.7697 286 


8.2670 294 


566 


32 03 56 


181 321 496 


23.7907 545 


8.2719 039 


567 


32 14 89 


182 284 263 


23.8117 618 


8.2767 726 


568 


32 26 24 


183 250 432 


23.8327 506 


8.2816 255 


569 


32 37 61 


184 220 009 


23.8537 209 


8.2864 928 


570 


32 49 00 


185 193 


000 


23.8746 728 


8.2913 444 


571 


32 60 41 


186 169 


411 


23.8956 063 


8.2961 903 


572 


32 71 84 


187 149 


248 


23.9165 215 


8.3010 304 


573 


32 83 29 


188 132 


517 


23.9374 184 


8.3058 651 


574 


32 94 76 


189 119 


224 


23.9582 971 


8.3106 941 


575 


33 06 25 


190 109 


375 


23.9791 576 


8.3155 175 


576 


33 17 76 


191 102 


976 


24: 


8.3203 353 


577 


33 29 29 


192 100 


033 


24.0208 243 


8.3251 475 


578 


33 40 84 


193 100 


552 


24.0416 306 


8.3299 542 


579 


33 52 41 


194 104 


539 


24.0624 188 


8.3347 553 


580 


33 64 00 


195 112 000 


24.0831 891 


8.3395 509 


581 


33 75 61 


196 122 941 


24.1039 416 


8.3443 41 


582 


33 87 24 


197 137 368 


24.1246 762 


8.3491 256 


583 


33 98 89 


198 155 287 


24.1453 929 


8.3539 047 


584 


34 10 56 


199 176 704 


24.1660 919 


8.3586 784 


585 


34 22 25 


200 201 625 


24.1867 732 


8.3634 466 


586 


34 33 96 


201 230 056 


24.2074 369 


8.3682 095 


587 


34 45 69 


202 262 003 


24.2280 829 


8.3729 668 



46* 



2K 



5^Q HAND-BOOK OF LAND AND MARINE JE^GINES. 

TABLE — (Concluded) 
OF SQUARES, CUBES, AND SQUARE AND CUBE ROOTS, ETC. 



Number. 


Square. 


Cube. . 


Square Root. 


Cube Root. 


588 


34 57 44 


203 297 472 


24.2487 113 


8.3777 188 


589 


34 69 21 


204 336 469 


24.2693 222 


8.3824 653 


1 590 


34 81 00 


205 379 000 


24.2899 156 


8.3872 065 


591 


34 92 81 


206 425 071 


24.3104 916 


8.3919 423 


592 


35 04 64 


207 474 688 


24.3310 501 


8.3966 729 


593 


35 16 49 


208 527 857 


24.3515 913 


8.4013 981 


594 


35 28 36 


209 584 584 


24.3721 152 


8.4061 180 


595 


35 40 25 


210 644 875 


24.3926 218 


8.4108 326 


596 


35 52 16 


211 708 736 


24.4131 112 


8.4155 419 


597 


35 64 09 


212 776 173 


24.4335 834 


8.4202 46 


598 


35 76 04 


213 847 192 


24.4540 385 


8.4249 448 


599 


35 88 01 


214 921 799 


24.4744 765 


8.4296 383 


600 


36 00 00 


216 000 000 


24.4948 974 


8.4343 267 


601 


36 12 01 


217 081 801 


24.5153 013 


8.4390 098 


602 


36 24 04 


218 167 208 


24.5356 883 


8.4436 877 


603 


36 36 09 


219 256 227 


24.5560 583 


8.4483 605 


604 


36 48 16 


220 348 864 


24.5764 115 


8.4530 281 


605 


36 60 25 


221 445 125 


24.5967 478 


8.4576 906 


606 


36 72 36 


222 545 016 


24.6170 673 


8.4623 479 


607 


36 84 49 


223 648 543 


24.6373 7 


8.467 


608 


36 96 64 


224 755 712 


24.6576 56 


8.4716 471 


609 


37 08 81 


225 866 529 


24.6779 254 


8.4762 892 


610 


37 21 00 


226 981 000 


24.6981 781 


8.4809 261 


611 


37 33 21 


228 099 131 


24.7184 142 


8.4855 579 


612 


37 45 44 


229 220 928 


24.7386 338 


8.4901 848 


613 


37 57 69 


230 346 397 


24.7588 368 


8.4948 065 


614 


37 69 96 


231 475 544 


24.7790 234 


8.4994 233 


615 


37 82 25 


232 608 375 


24.7991 935 


8.5040 35 


616 


37 94 56 


233 744 896 


24.8193 473 


8.5086 417 


617 


38 06 89 


234 885 113 


24.8394 847 


8.5132 435 


618 


38 19 24 


236 029 032 


24.8596 058 


8.5178 403 


619 


38 31 61 


237 176 659 


24.8797 106 


8.5224 321 


620 


38 44 00 


238 328 000 


24.8997 992 


8.5270 189 



HAND-BOOK OF LAND AND MARINE ENGINES. 547 

TABLE 

SHOWING THE TENSILE STRENGTH OF VARIOUS QUALITIES OF 
WROUGHT-IRON. 

American Wrought- Iron, 

Breaking weight of 
a square inch bar. 

From Salisbury, Conn 58,000 

" «' ** 66,000 

** l>ittsfield, Mass...... 57,000 

" Bellefonte, Pa 58,000 

" Maramec, Mo 43,000 

" ** 53,000 

" Centre County, Pa 58,400 

** Lancaster County, Pa 58,061 

** Carp River, Lake Superior 89,582 

** Mountain, Mo., charcoal bloom 90,000 

American, hammered 53,900 

Chain-iron 43,000 

Rivets 53,300 

Bolts 52,250 

Boiler-plates 50,000 

" 60,000 

Average boiler-plates ....♦,... » 55,000 

" joints, double-rivieted 35,000 

" " single " 28,600 

English and other Wrought- Irons, 

Iron, English bar , 56,000 

" mean of English 53,900 

*< rivets 65,000 

Lowmoor iron , 56,100 

** ** plates 57,881 

Bowling plates 53,488 

Glasgow best boiler 56,317 

" ship-plates 53,870 

Yorkshire plates. 57,724 

Staffordshire plates 43,821 

Derbyshire plates 48,563 

Bessemer wrought-iron 65,253 

" 76,195* 



548 HAND-BOOK OF LAND AND MARINE ENGINES. 

Breaking weight of 
a square inch bar. 

Bessemer wrought-iron 82,110 

Russian '' " 59,500 

'' 76,084 

Swedish '' " 58,084 

TABLE 

SHOWING THE ACTUAL EXTENSION OF WROUGHT-IRON AT 
VARIOUS TEMPERATURES. 
Deg. of Fah. Length. • 

. 32^ 1- 

212 .......1-0011356 

392 1-0025757^ Surface becomes straw-colored, deep 

672 1-0043253 y yellow, crimson, violet, purple, 

752 1-0063894 J deep blue, bright blue. 

932 .1-0087730 | Surface becomes dull, and then bright 

1112 1-0114811 I red. 

1652.... 10216024')^.,, , ,, ,,. , , 

2192 1-0348242 r"f. 'f^/'^^'^^ ^^^^^^S ^^^t' 

( white heat. 
2732 1-0512815) 

2912 Cohesion destroyed. Fusion perfect. 

Linear Expansion of Wrought-lron. — The linear ex- 
pansion a bar of wrought-iron undergoes, according to 
Danieirs pyrometer, when iieated from the freezing- to the 
boiling-point, or from 32° to 212° Fah., is about -qIq of 
its length; at higher temperatures, the elongation becomes 
more rapid. 

Thus, it will be seen how sensible a change takes place 
when iron undergoes a variation of temperature. A bar 
of iron, 10 feet long, subject to an ordinary change of 
temperature of from 32° to 180° Fah., will elongate more 
than i of an inch, or sufficient to cause fracture in stone 
work, strip the thread of a screw, or endanger a bridge, 
floor, roof, or trusses. 

The expansion of volume and surface of wrought-iron 
is calculated by taking the linear expansion as unity; 
then, following the geometrical law, the superficial expan- 



HAND-BOOK OF LAND AND MARINE ENGINES. 549 

sion is twice the linear, and the cubical expansion is three 
times the linear. 

Wrought-lron will bear on a square inch, without per- 
manent alteration, 17,800 pounds, and an extension in 
length of 74^0 u* Cohesive force is diminished ^-^qj^ by 
an increase of 1 degree of heat. 

Compared with cast-iron, its strength is 1*12 times, its 
extensibility 0*86 times, and its stiffness 1*3 times. 

TABLE 

SHOWING THE TENSILE STRENGTH OF VARIOUS QUALITIES OF 

STEEL PLATES. 

Breaking weight of 
a square inch bar. 

Mersey Co., puddled steel 108,906 

*< ** ship-plates 99,468 

Blochairn puddled steel 106,394 

'' boiler-plates 89,447 

Naylor, Vickers & Co., cast 87,972 

** " <* 95,190 

T. Turton & Son '. 95,360 

Moss & Gamble's 81,588 

Shortridge, Howell & Co 108,900 

Homogeneous metal 105,732 

" 2d quality 81,662 

Bessemer steel. 148,324 

** 154,825 

'' 157,881 

American chrome steel, highest strength 198,910 

" " lowest '« 163,760 

" ** '< average *' 180,000 

TABLE 

SHOWING THE TENSILE STRENGTH OF VARIOUS QUALITIES OF 
CAST-IRON. 

American Cast-Iron, 

Breaking weight of 
a square inch bar. 

Common pig-iron 15,000 

Good common castings 20,000 



550 HAND-BOOK OF LAXD AND MARINE ENGINES. 



1 



Breaking weight of 

a square inch bar. 

Cast-iron castings 20,834 

" 19,200 

27,700 

Gun-heads, specimen from 24,000 

*' 39,500 

Greenwood cast-iron 21,300 

" *' (after third melting) 45,970 

Mean of American cast-iron 31,829 

Gun-metal, mean 37,232 

English Cast- Iron-, 

Lowmoor 14,076 

Clyde, No. 1 16,125 

Clyde, No. 3 23,468 

Calder, No. 1 13,735 

Stirling, mean 25,764 

Mean of English 19,484 

Stirling, toughened iron , 28,000 

Carron, No. 2, cold-blast...... 16,683 

'' ** 2, hot-blast 13,505 

** *' 3, cold-blast 13,200 

'' ** 3, hot-blast 17,755 

Davon, No. 3, hot-blast 21,907 

Buffery, No. 1, cold-blast 17,466 

*' 1, hot-blast 13,437 

Cold-Talon (North Wales), No. 2, cold-blast 18,855 

*' 2, hot-blast 16,676 

Cast-lpon expands je^Voo ^^ ^^^ length for 1 degree of 
heat ; the greatest change in the shade, in this climate, is 
ttVo ^f ^^s length ; exposed to the sun's rays, y^'o o- 

Cast-iron shrinks, in cooling, from q\ to-g'^ of its length. 

Cast-iron is crushed by a force of 93,000 pounds upon 
a square inch, and will bear, without permanent alteration, 
15,300 pounds upon a square inch. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



551 





•J 
( 




M 
S 




CO 

00 


co 

cciw 


kO|M 


CO 

U1M 


tCJM 


CO 


fcO|M 




CO 


O 


CO 




rf^ 












OClM 






to 








00 
O 




00 

tO|M 


or 


CO 


Or 


o 
to 


4»M 


1— I 


1— I 

to 

1—1 


O) 







a- 


MlM 




CoiCT 


to 


4^P 


to 


oc|^ 


CO 


H-J^ 




(— ' 


Ox 


t— I 




ooico 






CO 


ccim 


o 

tC|M 


1— I 


1— » 

to 


1— I 


1— » 
CO 

Mm 


to 


Cn 


to • 


^ 


to 




to 

ool« 


to 
to 


to 


to 

CO 


to 

CDJCn 




to 


to 

00 


to 


M|M 


CO 


53 


CO 



^ 


H 


ct> 


P, 






cs 


^ 






cr 


D 


CQ 








"^ 


P 
O 


^ . 


isr' 






B* 


cc 


o 












m 






"9 






to 


Sj- 


tCH 


Ot 


OOM 


^J 


•-1^ 


IC|M 


o|" 


o 


rf4- 


to 


3=" 


h-i 




OJ 




t— ' 




^:r 


3- 


Wm 


to 

O 


i^ 


to 




to 


3- 


tiH 


to 


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to 


MlM 


§. 


tt»(W 


CO 

to 


$: 


CO 

cn 


OciM 




M|M 


§ 


h- k 



552 



HAND-BOOK OF LAND AND MARINE ENGINES. 






^ 
S 









3 






^4» 




<M 


o 

rH 


1—1 




wH« 


00 




t- 




o 


r-i 


iO 






1-H 


CO 


T-» 




t-loo , 


<M 


wl^ 


;? 


.o|=o 


rH 


Mn 


P^^ 






t: 


1 


2 
-t 

c 




a 




b 

'i 


> 

! 

b 



s? 


§ 


CO 


r4* 

?5 


CO 


^ 


CO 


g3 


CO 


r4* 
O 

CO 


CO 


00 


CO 




CO 


^ 












O 




00 




Ml'** 

rH 








CO 
rH 




t 


5 


a 


2 


-8 




1 
> 

i 

D 


s 
a 

s 



« 






eolrt* 
00 






to 


CO 


lO 






S 


If 


o 

CO 






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CO 




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s 






00 


.-to 


r+1< 


^ 




"^ 










i: 




or 

i 


1 




be 


c: 

p 


i * 


0) 



HAND-BOOK OF LAND AND MARINE ENGINES. 



553 



t ' 


3- 


o 




^-^ 


"i 


cr 


^ 

1 


3 

3* 

3 

2 






^§ 




a 


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CON 








^g' 




tf> 


^t- 


t-*o 




ON 




E? 




a 


^eo 


oog 




SI' 




kC 


M 


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a 


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toS 




gf 




^ 


M 


og 




gS? 




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ag? 




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Q 
W 
H 

O 



o 






o 
o 



tt 



5* 

CO 

: 


1 

5* 

o 


^ 

S 


00 




00 




00 

10|M 




00 




o 


h-k 


<o 

^M 


(—1 

00 


CO 




co 




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O 


1 


O 


CO 


O 


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CO 

MM 


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M|M 


1 


to 


i 


CO 



1 


p' 

r 


CO 


CO 




CO 




co 


^ 

iHm 


CO 


00 


►1^ 


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O 

UlM 


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to 

MM 










Oi 


g 


en 


i§ 


• ox 


to 


ox 




Ci 


kO|M 


>HM 


S3 


05 

MlM 


to 


05 

>*^p 


►Hm 


^ 


CJ1 

kO|M 


^ 

►H^- 


g 


-1 

Mm 







47 



554 



HAND-BOOK OF LAND AND MARINE ENGINES, 



TABLE 

SHOWING THE WEIGHT OF CAST- IRON PIPES, 1 FOOT IN LENGTH, 
FROM J INCH TO IJ INCHES THICK, AND FROM 3 TO 24 INCHES 
DIAMETER. 



2 

h 

a. 2 


Thickness in Inches. 


Lbs. 


1 
Lbs. 


Lbs. 


1 
Lbs. 


f 
Lbs. 


Lbs. 


1 
Lbs. 


H 
Lbs. 


Lbs. 


3 

H 

4 
6 

■?* 
? 
f 

11 

12 
13 
14 
15 
IG 
17 
18 
19 
20 
21 
22 
23 
24 


10 

iif 

13 
15 


12^ 

Hi 

16f 

18 

191 

2U 

23J 

25J 

27J 

29 

30| 

33 

34J 

3Gi 

38i 


17i 

19^ 

22" 

2^ 

27 

29J 

32 

Z^ 

36f 

39 

41| 

44J 

46J 

49 

51J 

54 

5GJ 

59 

61i 


221 

251 

28J 

311 

34J 

37^- 

40f 

43| 

46| 

50 

53 

561 

59 

62 

651 

681 

in 

761 
77J 
82| 
891 
951 


27i 

35 

38f 

42J 

46 

49$ 

53^ 

56f 

60f 

64J 

68} 

7l| 

75J 

79i 

82f 

8GJ 

90 

93J 

101} 

1081 

1151 

1234 

130i 

137 


























50^ 
54^ 
59 

63J 
67f 

72 

8o| 

fe4| 

89 

93J 

97| 

102 

106} 

110 J 

118} 

126J 

135} 

143 

152i 

161} 

169} 

178 


59 

63f 

68| 

73J 

78J 

83J 

88J 

93J 

98J 

103 

108 

112J 

117J 

122J 

127| 

137^ 

146} 

156} 

166 

178^ 

185} 

1951 

205} 

214 

223J 

233J 

245} 










78| 
84} 
89| 
95} 
lOOf 
10^ 
111| 
117J 
122f 
128J 
134 
139| 
145 
154 
165x 
176x 
187^ 
198^ 
209 
222^ 
233} 
243^ 
244| 
265^ 
277jj 


88J 

95 
101} 
107i 
113^ 
120 
125f 
132 
138 
144} 
150} 
156 J 
1622 
1731 
185} 
198 
211} 
223J 
235} 
247 
259 
273^ 
285:^ 
298^ 
310} 

































































































































HAND-BOOK OF LAND AND MARINE ENGINES. 



555 



TABLE 



SHOWING THE WEIGHT PER SQUARE FOOT OF WROUGHT-IRON, 
STEEL, COPPER, AND BRASS. 



'is 

Hi 




i 
II 

(Eg 

II 
1 


i 

u 


1 


.01 


.4049 


.4087 


.4625 


.4367 


.02 


.8098 


.8174 


.9250 


.8736 


.03 


1.2147 


1.2261 


1.3875 


1.3104 


.04 


1.6196 


1.6348 


1.8500 


1.7472 


.05 


2.0245 


2.0435 


2.3125 


2.1840 


.06 


2.4294 


2.4522 


2.7750 


2.6208 


.07 


2.8343 


2.8609 


3.3375 


3.0576 


.08 


3.2392 


3.2696 


3.7000 


3.4944 


.09 


3.6441 


3.6783 


4.1624 


3.9312 


.10 


4.0490 


4.^870 


4.6250 


4.3680 


.11 


4.4539 


4.4957 


5.0875 


4.8048 


.12 


4.8588 


4.9044 


5.5500 


5.2416 ! 


.13 


5.2637 


5.3131 


6.0125 


5.6784 1 


.14 


5.6686 


5.7218 


6.4750 


6.1152 i 


.15 


6.0735 


6.1305 


6.9375 


6.5520 1 


.16 


6.4784 


6.5392 


7.4000 


6.9888 


.17 


6.8833 


6.9479 


7.8625 


7.4256 


.18 


7.2882 


7.3566 


8.3250 


7.8624 


.19 


7.6931 


7.7653 


8.7875 


8.2992 


.20 


8.0980 


8.1740 


9.2500 


8.7368 


.21 


8.5029 


8.5827 


9.7125 


9.1728 


.22 


8.9078 


8.9914 


10.1750 


9.6096 


.23 


9.3127 


9.4001 


10.6375 


10.0464 


.24 


9.7176 


9.8088 


11.1000 


10.4832 


.25 


10.1225 


10.2175 


11.5625 


10.9200 


.26 


10.5274 


10.6262 


12.0250 


11.3568 


.27 


10.9323 


11.0349 


12.4875 


11.7936 


.28 


11.3372 


11.4436 


12.9500 


12.2304 


.29 


11.7421 


11.8523 


13.4125 


12.6673 


.30 


12.1470 


12.2610 


13.8750 


13.1040 


.31 


12.5519 


12.6697 


14.3375 


13.5408 


.32 


12.9568 


13.0784 


14.8000 


13.9776 


.33 


13.3617 


13.4871 


15.2625 


14.4144 


.34 


13.7666 


13.8958 


15.7250 


14.8512 


.35 


14.1715 


14.3045 


16.1775 


15.2880 



556 



HAND-BOOK OF LAND AND MARINE ENGINES. 



TA'Bl^'B — {Continued) ' 

SHOWING THE WEIGHT PER SQUARE FOOT OF WROUGHT-IRON, 
STEEIi, COPPER, AND BRASS. 



p 




l 




1 


£5 


bC3 


|| 






C30 


n 










hi 

1 


r 


f 


|l 


.36 


14.5764 


14.7132 


16.6500 


15.7248 


.37 


14.9813 


15.1219 


17.1125 


16.1616 


.38 


15.3862 


15.5306 


17.5750 


16.5984 


.39 


15.6911 


15.9393 


18.0375 


17.0352 


.40 


16.1960 


16.3480 


18.5000 


17.4720 


.41 


16.6009 


16.7567 


18.9625 


17.9088 


.42 


17.0058 


17.1654 


19.4250 


18.3446 


.43 


17.4107 


17.5741 


19.8875 


18.7824 


.44 


17.8156 


17.9828 


20.3590 


19.2192 


.45 


18.2205 


18.3915 ^ 


20.8125 


19.6560 


.46 


18.6254 


18.8002 


21.2750 


20.0928 


.47 


19.0303 


19.2089 


21.7375 


20.5296 


.48 


19.4352 


19.6176 


22.2000 


20.9664 


.49 


19.8401 


20.0263 


22.6625 


21.4032 


.50 


20.2450 


20.4350 


23.1250 


21.8400 


.51 


20.6499 


20.8437 


23.5875 


22.2768 


.52 


21.0548 


21.?524 


24.0500 


22.7136 


.53 


21.4597 


21.6611 


24.5125 


23.1504 


.54 


21.8646 


22.0698 


24.9750 


23.5872 


.55 


22.2695 


22.4785 


25.4375 


24.0240 


.56 


22.6744 


22.8872 


25.9900 


24.4608 


.57 


23.0793 


23.2959 


26.3625 


24.8976 


.58 


23.4842 


23.7046 


26.8250 • 


25.3344 


.59 


23.8891 


24.1133 


27.2875 


25.7712 


.60 


24.2940 


24.5220 


27.7500 


26.2080 


.61 


24.6989 


24.9307 


28.2125 


26.6448 


.62 


25.1038 


25.3394 


28.6750 


27.0816 


.63 


25.5087 


25.7481 


29.1375 


27.5184 


.64 


25.9136 


26.1568 


29.6000 


27.9552 


.65 


26.3185 


26.5655 


30.0625 


28.3920 


M 


26.7234 


26.9742 


30.5250 


28.8288 


.67 


27.1283 


27.2829 


30.9875 


29.2656 


.68 


27.5332 


27.7916 


31.4500 


29.7024 


.69 


27.9381 


28.3003 


31.9125 


30.1392 


.70 


28.3430 


28.6090 


32.3750 


30.5760 



HAND-BOOK OF LAND AND MARINE ENGINES. 



557 



TAIBI^'K- (Concluded) 

SHOWING THE WEIGHT PEE SQUARE FOOT OF WROUGHT-IRON, 
STEEL, COPPER, AND BRASS. 



So 

'^•^ si 


ii 
§1 


ft 
|l 

si 

too" 




Kg 

1 


.71 


28.7479 


29.0177 


32.8375 


31.0128 


.72 


29.1528 


29.4264 


33.3000 


31.4496 


.73 


29.5577 


29.8351 


33.7625 


31.8864 


.74 


29.9626 


30.2438 


34.2250 


32.3232 


.75 


30.3675 


30.6525 


34.6875 


32.7600 


.76 


30.7724 


31.0612 


35.1500 


33.1968 


.77 


31.1773 


31.4699 


35.6125 


33.6336 


.78 


31.5822 


31.8786 


36.0750 


34.0704 


.79 


31.9871 


32.2873 


36.5375 


34.5072 


.80 


32.3920 


32.6960 


37.0000 


34.9440 


.81 


32.7969 


33.1047 


37.4625 


35.3808 


.82 


33.2018 


33.5134 


37.9250 


35.8176 


.83 


33.6067 


33.9221 


38.3875 


36.2544 


.84 


34.0116 


34.3308 


38.8500 


36.6912 


.85 


34.4165 


34.7395 


39.3125 


37.1280 


.86 


34.8214 


35.1482 


39.7750 


37.5648 


.87 


35.2263 


35.5569 


40.2375 


38.0016 


.88 


35.6312 


35.9656 


40.7000 


38.4384 


.89 


36.0361 


36.3743 


41.1625 


38.8752 


.90 


36.4410 


36.7830 


41.6250 


39.3120 


.91 


36.8459 


37.1917 


42.0875 


39.7488 


.92 


37.2508 


37.6004 


42.5500 


40.1856 


.93 


37.6557 


38.0091 


43.0125 


40.6224 


.94 


38.0606 


38.4178 


43.4750 


41.0592 


.95 


38.4655 


38.8265 


43.9375 


41.4960 


.96 


38.8704 


39.2352 


44.4000 


41.9328 


.97 


39.2753 


39.6439 


44.8625 


42.3696 


.98 


39.6802 


40.0526 


45.3250 


42.8064 


.99 


40.0851 


. 40.4613 


45.7875 


43.2432 


100 


40.4900 


40.8700 


46.2500 


43.6800 



47* 



558 HAND-BOOK OF LAND AND MARINE ENGINES. 

RULES FOR FINDING THE DIAMETER AND SPEED 
OF PULLEYS. 

To find the Size of Driving-Pulley, — Multiply the di- 
ameter of the driven by the number of revolutions it 
should make, and divide the product by the revolutions 
of the driver. The quotient will be the size of the driver. 

EXAMPLE. 
Diameter of driven, 20 inches, 198 

Number of revolutions driven, 198, 20 

- " '' of driver, 220, 220)3960 

18 inch. 

The Diameter and Revolutions of Driver being given^ to 
find the Diameter of the Driven that shall make a given 
Number of Revolutions. — Multiply the diameter of the 
driver by its number of revolutions, and divide the pro- 
duct by the number of revolutions of the driven. The 
quotient will be the size of the driven. 

EXAMPLE. 

Diameter of driver, 18 inches, 220 

Number of revolutions of driver, 220, 18 

- " '' '' driven, 198, 198)"^ 

20 inch. 

To find the Number of Revolutions of the Driven Pulley, — 
Multiply the diameter of the driver by its number of rev- 
olutions, and divide by diameter of driven. The quotient 
will be the number of revolutions of the driven. 

EXAMPLE. 

Diameter of driver, 18 inches, 220 

Number of revolutions of driver, 220, 18 

Diameter of driven, 20, 2013960 

198 revolutions. 



N 
HAND-BOOK OF LAND AND MARINE ENGINES. 559 

GEARING. 

Gearing is the general term employed to denote a com- 
bination of mechanical organs, interposed between the 
prime mover and the working parts of machinery. Fre- 
quently, however, the signification is restricted to the 
series of toothed wheels by which the motion is con- 
ducted from one revolving axis to another, independently 
of the shafts and bearings by which they are supported. 
Two toothed wheels are also said to gear when they have 
their teeth engaged together ; and to be out of gear, when 
separate, and consequently out of action. 

Rule for finding the Diameter of Toothed Wheels, — 
Multiply the number of teeth by the number of thirty- 
seconds of an inch contained in the pitch, the product 
will be the diameter in inches and hundredths of an inch ; 
or, multiply the number of teeth by the true pitch, and 
the product by *3184. These results give only the di- 
ameter between the pitch-line on one side, and the same 
line on the other side, and not the entire diameter from 
point to point of teeth on opposite sides. It must also 
be borne in mind that these results are only approximate 
diameters, since the wheel often varies from the com- 
puted diameter in consequence of shrinkage and other 
causes. 

Rule for finding the Required Number of Teeth in a 
Pinion to have any given Velocity. — Multiply the velocity 
or number of revolutions of the driver by its number of 
teeth or its diameter, and divide the product by the desired 
number of revolutions of the pinion or driven. 

Rule for finding the Diameter of a Pinion, when the Di- 
ameter of the Driver and the Number of Teeth in Driver 
and Pinion are given, — Multiply the diameter of driver 
by the number of teeth in the pinion, and divide the pro- 



560 HAND-BOOK OF LAND AND MARINE ENGINES. 

duct by the number of teeth in the driver, and the quo- 
tient will be the diameter of pinion. 

Rule for finding the Number of Revolutions of a Pinion 
or Driven y when the Number of Revolutions of Driver and 
the Diameter or the Number of Teeth of Driver and Driven 
are given, — Multiply the number of revolutions of driver 
by its number of teeth or its diameter, and divide the 
product by the number of .teeth or the diameter of the 
driven. 

Rule for finding the Number of Revolutions of a Driver, 
when the Revolutions of Driven and Teeth, or Diameter of 
Driver and Driven, are given, — Multiply the number of 
teeth or the diameter of driven by its revolutions, and 
divide the product by the number of teeth or the diameter 
of driver. 

Rule for finding the Number of Revolutions of the last 
Wheel at the end of a train of Spur- Wheels, all of which 
are in a line, and mesh into one another, when the Revolu- 
tions of the First Wheel, and the Number of Teeth, or the 
Diameter of the First and Last are given, — Multiply the 
revolutious of first wheel by its number of teeth or its 
diameter, and divide the product by the number of teeth 
or the diameter of the last wheel ; the result is its number 
of revolutions. 

Rule for findiyig the Number of Revolutions in each 
Wlieel for a train of Spur- Wheels, each to have a given 
Velocity, — Multiply the number of revolutions of the 
driving-wheel by its number of teeth, and divide the pro- 
duct by the number of revolutions each wheel is to make. 
The results will be the number of teeth required for 
each. 

Rule for finding the Number of Revolutions of the Last 
Wheel in a train of Wheels and Pinions, Spurs or Bevels, 
when the Revolutions of the First or Driver, and the Diam- 



HAND-BOOK OF LAND AND MARINE ENGINES, 561 

eter, the Teeth or the Circumference of all the Drivers and 
Pinions are given, — Multiply the diameter, the circum- 
ference, or the number of teeth of all the driving-wheels 
together, and this continued product by the number of 
revolutions of the first wheel ; and divide this product by 
the continued product of the diameter, the circumference, 
or the number of teeth of all the pinions, and the quotient 
will be the number of revolutions of the last wheel. 

BELTING. 

While the use of belts for the transmission of power is 
not an American invention, the numerous improvements 
made in this country have caused it to be known in 
Europe as the American system. In Europe, the greater 
part of the power is transmitted by cog-wheels, but in this 
country, 99 per cent, is transmitted by belting. The latter 
is used everywhere, from the sewing-machine to the 500- 
horse-power engine of the largest factory. 

Belts can be run in any way, at any angle, of any length, 
and at any speed, and can be put up by any one of ordinary 
skill. They can be made of any flexible material — leather, 
rubber, gutta-percha, or cloth ; yet, while so handy and so 
popular, they have one fault — they are not positive. If 
the motor makes a certain number of revolutions, a por- 
tion of them are lost with every belt used. This is the only 
fault of the system. It is noiseless, yielding, and regular ; 
but, unlike cog-wheels, it is not positive. The number of 
revolutions that are lost may, and do, vary continually by 
changes of the load, or of the atmosphere. 

Belts derive their power to transmit motion from the 
friction between the surface of the belt and the pulley, and 
from nothing else, and are governed by the same laws«as 
in friction between flat surfaces. The friction increases 
regularly with the pressure. The great diflerence often 

2L 



562 HAND-BOOK OF LAND AND MARINE ENGINES. 

observed in the friction of belts is due simply to their 
elasticity of surface ; that is, the more elastic the surface, 
the greater the friction. 

Very careful experiments have been made, both in this 
country and in France, in regard to the transmitting 
power of flat leather belts, and the agreement of the 
results by independent investigators entitle them to great 
confidence. These experiments show how much power 
a belt can be expected to transmit with safety when 
various data are given ; but they do not show how much 
power can be transmitted by a belt. 

Take, for instance, two belts of the same width, the 
same condition, and the same quality of material, one of 
them is run so slack that it continually sags or flaps, 
while the other is strained so tight that it frequently 
breaks ; now, if both belts be run at the same speed, the 
tight belt will transmit nearly twice as much power as 
the slack one. Now, if the actual strain on both belts 
were known, and also the diameter and condition of the 
pulleys, the amount of power transmitted could be calcu- 
lated with considerable accuracy. 

Search may be made in vain for any such data, as the 
general rule for calculating the power a belt will transmit 
seems to be that an inch belt, with a speed of 1000 feet 
per minute, will transmit a horse-power, without taking 
into account the tension of the belt, diameter of pulleys, 
etc., points which have been determined by experiment to 
afiect the question materially. 

This seems to confirm the statement that power trans- 
mitted by belts is ordinarily estimated by guesswork, and 
also that the guesses are quite as likely to be wrong as 
right; therefore, it is not to be wondered at that there 
should be numerous quarrels and lawsuits between land- 
lords and their tenants in regard to the power used by the 
latter. 



HAKD-BOOK OF LAND AND MAEINE EKGINES. 



663 



On the scientific principle that the adhesion, and con- 
sequently the capability of leather belts to transmit power 
from motors to machines, is in proportion to the pressure 
of the actual weight of the leather on the surface of the 
pulley, it is manifest that, as longer belts have more weight 
than shorter ones, and that broader belts of the same 
length have more weight than narrower ones, it may be 
adopted as a rule that the adhesion and capability of belts 
to transmit power, is in the ratio of their relative lengths 
and breadths. 

A belt of double the length or breadth of another, under 
the same circumstances, will be found capable of trans- 
mitting double the power. For this reason it is desirable 
to use long belts. By doubling the velocity of the same 
belt, its effectual capability for transmitting power is also 
doubled. 




Improved methods of Lacing Belts. 

It is a common error, among mechanics and owners of 
factories, to make the face of their pulleys narrow, in order 
to economize on the first cost of pulleys and belting ; but 
this false economy seldom decreases the cost of pulleys, 
and only saves a trifle in the first cost of belting. The 
small amount saved is soon lost by the stopping of 



564 HAND-BOOK OF LAND AND MARINE ENGINES. 

machinery caused by the slipping of belts, strain on the 
shafting, increased friction, requiring additional driving- 
power, and rapid destruction of the belts themselves. 

Leather belts used with grain side to the pulley, will not 
only do more work, but last longer than if used with flesh 
side to the pulley. This is owing to the fact that the grain 
side is more compact and fixed than the flesh side, and 
more of its surface is brought in contact with the pulley. 

The smoother the two surfaces, the less air will pass 
between the belt and the pulley. The more uneven the 
surface of the belt and pulley, the more strain necessary 
to prevent the belt -slipping ; for what is lost by want of 
contact, must be made up by extra strain on the belt. 

Leather belts, with grain side to pulley, can drive 3.1 
per cent, more than flesh side ; for this reason, in all cases 
where the face of pulleys are not turned and polished, 
they should be covered with leather. 

A belt should be pliable, so as to adjust itself readily 
to the pulley as it passes over it. If the belt be pliable, 
its contact surface smooth and polished, and it runs 
on a pulley whose surface is perfectly smooth, there is 
obtained the full benefit of the atmospheric pressure upon 
the belt as it passes over the pulley, minus the centrifugal 
force caused by its motion. 

Belts should never be oiled except when they become 
dry and hard; and then the oil should be used very 
sparingly, as it not only rots the leather, but causes the 
belt to stretch. 

In oiling or greasing a belt, avoid everything of a pasty 
nature. The belt should be made pliable, not covered 
with a sticky substance. 

Horizontal Belts.— The driving half of horizontal belts 
should be the lower half^ when practicable, as, when the 
belt stretches, the upper half will cover more of the 



HAND-BOOK OF LAND AND MARINE ENGINES. 565 

pulley's surface. Long horizontal belts are better than 
short ones, as their weight increases their contact with the 
pulley. 

Perpendicular Belts.— Belts running on pulleys perpen- 
dicular to each other, should be kept tightly strained, as 
their weight tends to decrease their contact with the lower 
pulleys. 

In putting on a new belt or taking up an old one, 
great care should be taken to have the ends perfectly 
square, and the lace- or hook-holes punched exactly oppo- 
site to each other. Many fail in these respects, and in 
consequence have crooked belts. 

A good leather belt, one inch wide, has sufficient strength 
to lift 1000 pounds. 

The speed of a mile per minute, for main driving leather 
belts, has been found both safe and advantageous for prac- 
tical use. 

The capability of belts to transmit power is determined 
by the extent of their adhesion to the surface of pulleys. 

The extent of the adhesion of belts varies greatly under 
the varying circumstances in the use of them, and is 
limited in comparison with the absolute strength of the 
leather. 

The adhesion and friction causing the belt to cling to 
the surface of a pulley without slipping, is mainly governed 
by the weight of the leather — if used horizontally. 

If belts are strained tightly on the pulleys, then the 
adhesion is increased m proportion to the increased ten- 
sion produced. 

Double Leather Belts. — Double leather belts are fre- 
quently used ; but it is clearly a mistake, as a single leather 
one will transmit more of the power than a double one. 
Double leather belts run straighter than single ones, as 
the flank side of One part can be put against the back of 
48 



566 HAND-BOOK OF LAND AND MARINE ENGINES. 

the others. A double belt will stand a greater tension 
than a single one, but a single one will stand all that 
should be put upon any belt. 

Rubber Belts. — A rubber belt will transmit as much 
power as a leather belt with the same tension, and will 
last as long, and run perfectly straight. It can be made 
of any length or width, of exactly the same thickness in 
every part, perfectly smooth on its surface, and, when in 
use, every part will come in contact with the face of the 
pulley. The greater tractile power of a rubber belt is due 
to its surface elasticity. 

Rule for finding Length of Belt wanted. — Add the 
diameter of the two pulleys together; divide the sum by 2 
and multiply the quotient by 3|. Add the product to 
twice the distance between the centres of the shafts, and 
the sum will be the length required. 

Rule for finding the Width of Belt to Transmit a given 
Horse-power, — Multiply 36,000 by the number of horse- 
power. Multiply the speed of the belt io feet per minute 
by one-half the length in inches of belt in contact with 
smaller pulley. Divide the first product by the second. 
The quotient will be the required width in inches. 

Another \{\x\q for finding the Width of Belt, etc, — Multiply 
36,000 by the number of horse-powers ; divide the product 
by the number of feet the belt is to travel per minute ; 
now, divide the quotient by the number of feet, or parts 
of feet, of belt in contact with the smaller pulley ; divide 
this last quotient by 6, and the result is the required width 
of belt in inches. 

Rule for finding the Change required in the Length of a 
Belt when one of the Pulleys on which it runs, is changed for 
one of a Different Size, — Take three times the difierence 
between the diameters of the pulleys, and divide by 2. 
The result will be the length of belt to cut out or put in. 



HAND-BOOK OP LAND AND MARINE ENGINES. 567 

Rule jor calculating the Number oj Horse-powers a Belt 
will Transmit; its Velocity, and the Number of Square Inches 
in contact with the Smaller Pulley being given, — Divide the 
number of square inches in contact with the pulley by 2 ; 
multiply this quotient by the velocity of the belt in feet 
per minute, and divide by 36,000. The quotient is the 
number of horse-powers the belt will transmit. 

How to Test the Quality of Leather for Belting. — Cut 
a small strip of the leather about ^^ of an inch in thick- 
ness, and place it in strong vinegar. If the leather has 
been thoroughly tanned, and is of good quality, it will 
remain for months even, immersed, without alteration, 
simply becoming a little darker in color. But, on the 
contrary, if not thoroughly tanned, the fibres will quickly 
swell, and after a short period become transformed into a 
gelatinous mass. 

How to Make Belts Run on the Centre of Pulleys.— It 
is a common occurrence for belts to run on one side of the 
pulleys. This arises from one or two causes : 1st, one or 
both of the pulleys may be conical, and of course the belt 
will run on the higher side. The raost effectual remedy for 
this would be to straighten the face of the pulleys. 2d, 
the shafts may not be parallel, or exactly in line. In this 
case, the belt would incline off to the side where the ends 
of the shafts came nearest together. The remedy in this 
case, would be to slack up on the hanger-bolts, and drive 
the hangers out or in, as the ease may be, until both ends 
of the shaft become exactly parallel. This can be deter- 
mined by getting the centres of the shafts at both ends, by 
means of a long lathe or light strip of board. 

Tighteners. — The tightener should be placed as close to 
the large or driving pulley as circumstances will permit, 
as the loss of power incurred by the use of the tightener 
is equal to that required to bend the belt and carry the 



568 HAND-BOOK OF LAND AND MAKINE ENGINES. 

tightening pulley. Consequently, there is a greater loss of 
power by placing it near the small pulley, as the belt is 
required to be bent more than when it is placed near the 
large one. 

CEMENT FOR MAKING STEAM- JOINTS AND PATCHING 
STEAM-BOILERS. 

Take a quantity of pure red lead, put it in an iron 
mortar, or on a block, or thick plate of iron. Put in a 
quantity of white lead ground in oil ; knead them together 
until you make a thick putty, then pound it ; the more 
it is pounded, the softer it will become. Roll in red lead 
and pound again ; repeat the operation, adding red lead 
and pounding until the mass becomes a good stiff putty. 
In applying it to the flange or joint, it is well to put a thin 
grummet around the orifice of the pipe to prevent the 
cement being forced inward to the pipe, when the bolts 
are screw^ed up. 

When the flanges are not faced, make the above mass 
rather soft, and add cast-iron borings run through a fine 
sieve, when it will be found to resist either fire or water. 

Another Cement — Take 10 pounds of ground litharge, 
4 pounds of ground Paris white, ^ pound of yellow ochre, 
and ^ ounce of hemp, cut into lengths of ^ inch ; mix all 
together with boiled linseed-oil, to the consistency of a 
stiff putty. This cement resists fire, and will set in . 
water. 

Cement for Rust- Joints, — Cast-iron borings or turnings, 
19 pounds ; pulverized sal-ammoniac, 1 pound ; flour of 
sulphur, ^ pound. Should be thoroughly mixed and 
passed through a tolerably fine sieve. Sufficient water 
should be added to wet the mixture through. It should 
be prepared some hours . before being used. A small 



HAND-BOOK OF LAND AND MARINE ENGINES. 569 

quantity of sludge from the trough of a grinding-stone 
will improve its quality. 

NON-CONDUCTORS FOR STEAM-PIPES AND STEAM- 
CYLINDERS. 

A very cheap and efficient non-conductor for covering 
steam-pipes and cylinders may be prepared in the follow- 
ing proportions: — 100 pounds of fire or potter's clay, 
dissolved in water and thoroughly mixed with 100 pounds 
of finely-sieved coal ashes, and 1^ pounds of hair. After 
being well kneaded together, it should be allowed to stand 
a few hours in a damp place. Just before being used, 100 
pounds of plaster of Paris should be added, which, being 
thoroughly mixed, may be laid on the surface to be 
covered, in a thin coat, with a trowel, and when dry 
another may be added, and so on until the desired thick- 
ness is attained, after which the surface should be made 
as smooth as possible. It can then be whitewashed or 
painted any desired color, and made to look quite orna- 
mental. The pipe or cylinder should be warm when the 
non-conductor is applied. 

HOW TO MARK ENGINEERS^ OR MACHINISTS' 
TOOLS. 

Any engineer or machinist can mark his name on his 
tools by first warming the tool to be marked, and rubbing 
on a thin layer of beeswax or tallow until it flows, and 
then letting it cool ; after which the name may be marked 
with a dull scriber or a piece of hard wood sharpened to 
a point; then, by applying some nitric acid for a few 
minutes, the name will be found etched on the steel; after 
which the acid must be thoroughly washed ofi* with water, 
and the tool again heated in order to remove the wax or 
tallow, and rubbed over with a soft rag. 
48* 



570 HAND-BOOK OF LAND AND MARINE ENGINES. 

TO POLISH BRASS. 

Engineers will find the following recipe a good one for 
polishing the brass work of their engines: Oxalic acid, 
dissolved in rain- or cistern- water, in the proportion of 
about five cents' worth to a pint of water, if applied with a 
rag or piece of waste, will remove the tarnish from brass, 
and render it bright ; the surfixce should then be rubbed 
with an oily rag and dried, and afterwards burnished with 
chalk, whiting, or rotten-stone. This is probably one of 
the quickest known methods for cleaning brass. A mix- 
ture of muriatic acid and alum, dissolved in water, imparts 
a golden color to brass articles that are steeped in it for a 
few seconds. 

Owing to irregularities of surface, it often happens that 
considerable difficulty is encountered in putting a good 
polish on articles of brass or copper. If, however, they be 
immersed in a bath composed of aquafortis, 1 part ; spirits 
of salt, 6 parts ; and water, 2 parts, for a few minutes, if 
small, or 20 or 30 if large, they will become covered with 
a kind of black mud, which, on removal by rinsing, dis- 
plays a beautiful lustrous under-surface. Should the 
lustre be deemed insufficient, the immersion may be re- 
peated, care always being taken to rinse thoroughly. 
All articles cleaned in this manner should be dried in hot, 
dry sawdust. 

SOLDER. 

The following solder will braze steel, and may be found 
very useful in case of a valve-stem, or other light portion, 
breaking, when it is important that the engine should con- 
tinue work for some time longer: Silver, 19 parts ; copper, 
1 part; brass, 2 parts. If practicable, charcoal dust 
should be strewed over the melted metal of the crucible. 



HAND-BOOK OF LAND AND MARINE ENGINES. 



571 



TABLE 

SHOWING WEIGHT OP DIFFERENT MATERIALS. 



Mercury 

Lead 

Wrought-iron. 

Cast-iron 

Sheet Copper.. 
Cast Copper .. 

Cast Brass 

Brick 

Stone 

Water 



Weight of 

cubic feet 

in lbs. 


Weight of 

a cubic inch 

in ozs. 


848 


7.851 


709 


6.456 


477 


4.140 


454J 
557^ 
549} 
524i 
125 


4.203 
5.159 
5.086 
4.852 
1.456 


151 


1.396 


m 


0.579 



Number of 

cubic inches 

in a lb. 



2.037 

2.437 

3.623 

3.802 

3.103 

3.146 

3.223 

13.824 

11.443 

27.50 



Weight of 

a cubic inch 

in lbs. 



.4908 

.4103 

.276 

.263 

.3225 

.3178 

.3037 

.0723 

.0873 

.0362 



JOINTS. 

Rust-joints, composed of sal-ammoniac, iron borings, 
flour of sulphur, and water, were formerly employed for 
all the permanent joints around engines ; but they are 
fast going out of use and being replaced by faced joints. 

Red lead joints were also very generally used, but they 
are now obsolete, and justly so, not only for their dirty 
appearance, but also for the difficulty experienced in start- 
ing them, as it required, in most cases, the use of sledges 
and chisels, which incurred the danger of breaking the 
flanges. 

All movable joints of the best description of land and 
marine engines are now faced on a lathe or planer, and 
then rendered perfectly steam-, air-, and water-tight, by 
filing and scraping, so that all that is necessary, when put 
together, is to oil their surfaces. 

For smooth surfaces that can be conveniently calked, 
sheet copper, annealed by heating it to a cherry red, and 
then plunging it in cold water, makes a permanent joint. 



572 HAND-BOOK OF LAND AND MARINE ENGINES. 

Lead wire makes a very cheap, clean, and permanent 
joint. Copper wire also makes a very good joint; but, 
when convenient, it is always best to plane or turn a 
groove in one of the surfaces to be brought in contact 

For uniform surfaces, gauze wire-cloth, coated on either 
side with white or red lead paint, makes a very durable 
joint, particularly where it is exposed to high tempera- 
tures. 

For pumps or stand-pipes in the holds of vessels, canvas 
well saturated on both sides with white or red lead, makes 
a very durable joint. Pasteboard, painted on both sides 
with white or red lead paint, is frequently used with good 
results. 

Gum is now very generally used for steam- and water- 
joints, and is very convenient, as it requires no prepara- 
tion, special tools, or much experience to use it ; for rough 
or uneven surfaces, it is more reliable than any other 
material used for joints. But it has the defect of being 
very injurious to iron in consequence of the great quantity 
of sulphur it contains. 

Cooling Compound for Heavy Bearings. — For cooling 
heavy pillow-block bearings, or the steps of upright shafts, 
the following will be found very valuable : 4 pounds of 
tallow, \ pound sugar of lead, and | pound of plumbago. 
When the tallow is melted (not boiling), add the sugar of 
lead, and let it dissolye ; then put in the plumbago. Keep 
stirring until the whole mass is cold. 

A mixture of soft soap and black lead makes an excel- 
lent lubricant for gearing, as it lessens the abrasion and 
noise, and has the advantage over tallow of not becoming 
hard. It is also easily removed should it become neces- 
sary to clean the parts on which it has been used. 



HAND-BOOK OF LAND AND MARINE ENGINES. 573 

STEAM-BOILER FLUE AND TUBE CLEANERS. 

Steam is more effectual and convenient than any other 
known method for cleaning the tubes of steam-boilers, as 
the operation may be easily performed while the furnace 
is in full blast. The steam may be taken from any con- 
venient place by means of a gum hose, about one inch in 
diameter, attached to a valve by means of a nipple, the 
other end of the hose being securely fastened to a piece 
off inch gas-pipe of the desired length, which should also 
be furnished with a v^lve. This pipe should be covered 
with wood, which may be secured at each end by means 
of ferules. 

To clean tubes by this method, the valve in the nozzle- 
pipe should be first closed ; then open the supply steam 
and also the damper, and insert the nozzle-pipe in each 
tube or flue, and then turn on the steam, when all the 
deposit, ashes, etc., will be blown into the ash-pit. To 
clean the tubes of vertical boilers, the nozzle-pipe should 
be bent in order to make it capable of being inserted in 
the vertical tubes. 




Pike's Boiler Tube and Flue Cleaner. 

The annexed cut represents Pike's Steam-Boiler Flue 
and Tube Cleaner. It will be observed that the tubes of 
the cleaner, through which the steam escapes, are twisted 
into a spiral form, causing the steam to pass through the 
flue or tube in a spiral course, thereby effectually removing 
all the dust or ashes. This tube-cleaner is highly spoken 
of by engineers and steam users in general. It is the 
invention of Wm. G. Pike, an inspector of the Hartford 
Steam-Boiler Inspection and Insurance Company. 



574 HAND-BOOK OF LAND AND MARINE ENGINES. 

THE INVENTION AND IMPROVEMENT OP THE 
STEAM-ENGINE. 

A Machine receiving at distant times and from many 
hands new combinations and improvements, and becoming 
at last of signal benefit to mankind, may be compared to 
a rivulet, swelled in its course by tributary streams, until 
it rolls along a majestic river, enriching in its progress 
states and provinces. In retracing the current from where 
it mingles with the ocean, the pretensions of even ample 
subsidiary streams are merged in our admiration of the 
master flood, glorying, as it were, in its expansion. But 
as we continue to ascend, those waters which nearer the 
sea would have been disregarded as unimportant, begin to 
rival in magnitude, and divide attention with the parent 
stream, until at length, on approaching the fountains of 
the river, it appears trickling from the rock, or oozing 
from among the flowers of the valley. 

So also in developing the rise of a machine, a coarse 
instrument or a toy may be recognized a& the germ of 
that production of mechanical genius whose power and 
usefulness have stimulated our curiosity to mark its 
changes and to trace its origin. The same feeling of grati- 
tude which attached reverence to the spot from whence 
mighty rivers have sprung, also clothed it, as it were, 
with divinity, and raised altars in honor of the inventors 
of the saw, the plough, and the loom. To those who are 
familiar with modern machinery, the construction of these 
implements may appear to have conferred but slight claim 
to the respect in which their authors were held, in ancient 
times. Yet, artless as they seem, their use first raised man 
above the beasts of the field, by incalculably diminishing 
the sum of human labor. 

From the important and. increasing influence of the 



HAND-BOOK OF LAND AND MARINE ENGINES. 575 

steam-engine on human affairs, controversies have fre- 
quently arisen between writers of different nations respect- 
ing the claims of their countrymen to its invention. But 
the steam-engine cannot be said to be the invention of any 
one man or belong to any nationality, but to be a com- 
bination of the scattered devices of a number of ingenious 
men, whose fortune it was more frequently to fail than to 
succeed, but who did not consider such failures a good 
reason for abandoning their cherished objects, or allowing 
them to fall into oblivion, being aware that practice is 
progressive, and that the mechanical difBculties which 
so much embarrassed them would be removed as they 
advanced towards greater perfection, and that the schemes 
that had failed, as well as those that were doubtful, should 
be considered as seeds drifting on a common field which 
some random step would fix in the soil and quicken into 
life. 

It also not unfrequently happened that some of those 
discoveries that conferred such benefits on mankind were 
the result of mere accident, and that, while in the pursuit 
of some peculiar objects, others of greater importance were 
often unfolded. Such was the case of the steam-engine, as 
it was only the raising of water directly by fire that exer- 
cised the ingenuity of Worcester, Moreland, Papin, Savery, 
and Newcomen. But their labors resulted in the produc- 
tion of the most important and valuable machine that the 
arts ever presented to man — the steam-engine. 

The earliest records extant of a machine producing use- 
ful effect by the vapor of boiling water, is the Eolipiie of 
Heron, of Alexandria, who lived about 280 years B. C, 
and which may be said to be the " germ " of the modern 
steam-engine. The EoHpile was a hollow globe resting 
on legs, which, being filled with water and placed over a 
fire, allowed the increasing steam to escape through a 



576 HAND-BOOK OF LAND AND MARINE ENGINES. 

small orifice at the top, which had the effect of producing 
a draught similar to that of the blower-pipe in the chim- 
ney of a locomotive. The Eolipile was very extensively 
used in Egypt for blowing fires, increasing draught in 
chimneys, diffusing perfumes, and for idol worship, etc. 

In 1543, Blasco d'Garay, a Spaniard^ is said to have 
constructed a steamboat of 200 tons, in the harbor of Bar- 
celona, Spain, and used steam as a motive-power for its 
propulsion. From this it was claimed that the steam- 
engine was invented in Spain, and that Blasco d^Garay 
should be regarded as the inventor. But as the nature 
and construction of his engine are not mentioned in the 
claim, we are left to form our own opinion. The proba- 
bilities are that D'Garay used a machine constructed on 
the same principle as Savery's, Papin's, or Leopold's, to 
raise water upon an overshot-wheel fixed on the same 
axle as the paddles. D'Garay is also claimed to be the 
inventor of the paddle-wheel, which is evidently a mistake, 
as the same honor was claimed by Papin, Savery, Jouffroy, 
Symington, and a host of others. In fact, the principle of 
the paddle-wheel is equally as old as the wind-mill. 

In 1630, Branca, an Italian, is claimed to have invented 
a machine which produced useful effect by the elastic force 
of steam. But from the most reliable accounts, Branca's 
machine was constructed on the same principle as the 
" breast " water-wheel, and received its motion from steam 
issuing from an orifice in a vessel similar to the Eolipile. 

In 1663, the Marquis of Worcester is said to have con- 
structed an engine by which motion was given to a piston 
by means of steam. But the account of his invention is 
so ambiguous as to lead to the belief that his machine was 
similar to those of Papin and Savery, which could not be 
said to belong to the same class as the modern steam- 
engine, nor could their inventors claim to have contributed 



HAND-BOOK OF LAND AND MAKINE ENGINES. 577 

anything to the invention of the latter, except to make 
their contemporaries more familiar with the mechanical 
properties of steam, as their ideas seem to have been 
wholly confined to the raising of water in the most direct 
manner. There is no evidence to show that either Papin 
or Savery ever jjiought of a piston. 

In 1710, Newcomen made the first steam-engine in 
England that could be said to be worthy of the name. 
To Newcomen belongs the honor of not only laying the 
foundation of the modern steam-engine, but also of attract- 
ing the attention of ingenious men to its improvement. 
Newcomen was also claimed to be the discoverer of the 
principle of condensation ; but this is evidently a mistake, 
as the alchemists were familiar with the formation of a 
vacuum by the condensation of steam, and with raising 
water into it by atmospheric pressure, long before New- 
comen's time. 

In 1720, Leopold and Trevithick invented their high- 
pressure engine, which was greatly admired, though useless 
and impracticable, for when the steam raised the piston to 
the upper end of the cylinder it would remain there, as 
there was no counter-pressure to cause it to descend. But 
the engines of Newcomen and Leopold, with all their 
imperfections, were the connecting links between the 
machines of Heron, D'Garay, Papin, and Savery, and the 
engines of Watt, Fitch, and Oliver Evans. 

In 1764, James Watt made the first engine in England 
that bore any resemblance to steam-engines of the modern 
type ; and in 1786, he patented and made public his great 
improvements, among which was separate condensation — 
to realize the importance of which requires careful study 
and thorough mechanical knowledge even at this late day. 
When we consider that to him all was com[)aratively 
novel, we pause in astonishment at the stupendous results 
49 2M 



578 HAND-BOOK OF LAND AND MARINE ENGINES. 

of his invention; and yet it was eight years before he 
succeeded in getting any one to try it, and had not a for- 
tunate chance at that period introduced him to a liberal, 
enlightened, and enterprising man in Boulton, another 
eight years of fruitless efforts might probably have been 
undergone, or even the full appreciation of the invention 
indefinitely delayed, in which case the whole of that 
vast career of progress on which the human race entered 
as a consequence of the steam-engine would have been 
postponed. 

In 1787, John Fitch, of Connecticut, with the aid of a 
common blacksmith, built in Philadelphia the first con- 
densing-engine ever heard of on this continent, and this 
without any knowledge of Watt's improvements in con- 
densing-engines, as it was in the previous year that the 
latter patented and made them public — consequently, 
there is every reason to believe that John Fitch was en- 
tirely ignorant of them. 

In 1793, Oliver Evans, a native of Philadelphia, invented 
the high-pressure engine, and to him must be awarded 
the credit of having built, and put in operation, the first 
practically useful high -pressure steam-engine. The high- 
pressure engine of Oliver Evans had immense advantages, 
in its cheapness and simplicity, over the more expensive 
and complicated condensing-engine of Watt, and ever 
since the days of Oliver Evans, the high-pressure engine 
has continued to be the standard steam-engine for land 
purposes wherever steam has been introduced as a motive- 
power. England, ever true and grateful to her own 
genius, has fitly honored her greatest inventor, Watt ; while 
America has suffered the genius of Oliver Evans, John 
Fitch, and Robert Fulton, to die unrewarded in life, and 
forgotten in the grave, though she has not forgotten to 
profit by their inventions. 



HAND-BOOK OF LAND AND MARINE ENGINES. 579 

In 1807, Robert Fulton, a man whom we should never 
forget to honor, established the success of steam naviga- 
tion. He was also the first to apply the paddle-wheel, in 
its present form, to the propulsion of vessels, and to intro- 
duce steam ferry-boats in this country. 

It is quite interesting to follow the various improve- 
ments that have been made upon the steam-engine at dif- 
ferent times, and to see how it has been brought to its 
present form. The cylinder and piston were used for 
raising water long before the advent of the steam-engine ; 
and in the early forms of the latter, one end of the cylin- 
der was open to the atmosphere, while the piston was 
nothing more than a flat wooden float, connected with a 
beam and sector by means of a rod and chain. But in 
1776, Blakey made the piston steam-tight by means of a 
stratum of hemp saturated with grease, for which he 
obtained a patent. 

In 1804, Oliver Evans made the cylinder a steam-tight 
vessel, and introduced steam alternately above and below 
the piston. In this arrangement lay the vital energy of 
the steam-engine, as all the other parts are but appendages 
to the cylinder and piston. They may be removed, and 
the energy of the machine still remains ; but take away 
either cylinder or piston, and the whole becomes inert as 
the limbs of an animal whose heart has ceased to beat. 
The metallic piston-packing, now so universally used, was 
invented by Aiken in 1836, and the stufiing-box, by La 
Hire, in 1716. 

Murdock was claimed to be the inventor of the crank, 
but the same device had been used in the common foot- 
lathe centuries before. After many years of experiment, 
it was finally adopted by Pickard ; after which Watt 
patented a much more complicated method of transmit- 
ting reciprocating into rotary motion, which was called 



580 HAND-BOOK OF LAND AND MARINE ENGINES. 

the sun and planet motion, but it went out of use after 
repeated trials with the crank. 

In the first steam-engines, the admission of the steam to 
the cylinder was regulated by means of a stop-cock, which 
required constant attention, as it had to be opened and 
closed at each stroke of the piston; but a boy, named 
Potter, employed in this service, stimulated by the love 
of play, ingeniously added cords to the levers by which 
the cocks were turned, and connecting the other ends of 
the cords to the working-beam, rendered the machine 
self-acting. Beighton afterwards substituted iron rods. 

The parallel rods, now so universally superseded by the 
guides, were invented by Watt in 1790. He was also the 
inventor of the condenser, and the first to attach an air- 
pump to the steam-engine, though the latter device was 
used for other purposes previous to Watt's time. Watt 
was also the inventor of the governor ; but that indispen- 
sable adjunct of the steam-engine remained very imperfect 
down to 1848, when George Corliss invented and con- 
structed the first steam-engine governor that could be 
said to be worthy of the name. 

The slide-valve was invented by Murray, in 1810. In 
1832, R. L. Stevens invented the poppet-valve. In 1841, 
he invented the Stevens cut-oflT valve-gear, which is still 
used on a large number of marine engines. He was also 
the inventor of the now universally known American 
skeleton walking-beam, with cast-iron centime and forged 
straps. 

In 1848, the automatic cut-off, which has almost univer- 
sally superseded that relic of barbarism, the throttle- 
valve, was invented by George Corliss. 

The combination of the foregoing devices has made 
up the modern steam-engine — the great prime mover of 
man. And, strange as it may seem, nearly all the im- 



HAND-BOOK OF LAND AND MARINE ENGINES. 581 

portant improvements in the steam-engine have been 
achieved by men of other callings than that of engineers, 
which goes to strengthen the often repeated assertion, that 
where it is possible to make any improvement in a ma- 
chine, it would be more likely to be discovered by men of 
natural genius, untrammelled by the routine of any special 
trade, than by men who, from force of habit, become unrea- 
soning creatures. 

While the merit of the discovery of the expansive 
properties of steam is due to Hornblower, who obtained a 
patent for his invention in 1781, the honor of first 
working it expansively belongs to Robert L. Stevens, as he 
invented the cut-o£f valve in 1813, and there does not 
appear to be any evidence that steam was worked expan- 
sively in England previous to that time. Thus it will be 
seen that most of the great improvements made in the 
steam-engine, more particularly the high-pressure engine, 
were the results of American genius ; and that America 
has produced a class of engineers who, in spite of many 
difficulties, have produced efiects wonderful even to them- 
selves. 

Although Archimedes was the inventor, or at least the 
alleged inventor, of the screw. Col. John Stevens, an 
American, was the first to adapt it to the purposes of the 
propulsion of vessels, in 1804. He was also the inventor 
of the tubular boiler. 

The spring-gauge, that invaluable attachment of the 
steam-boiler, is also an American invention, and with the 
exception of the Bourdon (French) and Schseffer (Prus- 
sian), all the spring-gauges in use in the United States, 
some thirty in number, are American inventions. 
49* 



INDEX. 



Absolute motion, 502. 

zero, 316. 
Accelerated motion, 503. 
Acceleration, 490. 
Accumulation of deposits, 459. 
Actual or net horse-power, 61. 
Adjustable injector, method of 
working the, 173. 
Sellers', 174. 
Advantages of high-pressure en- 
gine, 54. 
Affinity, 489. 
Air, 309, 380. 

and fuel, mixture of, 335. 
leakage of, 261. 
pressure of, 310. 
pump-cover, 260. 
pump, in its seat, placing the, 271. 
pumps, 222. 
Allen governor, 142, 143. 

high-pressure cut-off engine, 155, 
161. 
American coal and coke, table 
showing nature and value of 
varieties of, 343. 
woods, table showing prominent 
qualities in principal, 344. 
Amount of mechanical power, 288. 

of resisting pressure, 201. 
Analysis of anthracite, 336. 
Angle, 490. 
Angular advance, 106. 

motion, 503. 
Anthracite coal, 336. 

composition of different kinds of, 

336. 
evaporative eflaciency of a pound 
of, 337. 



Anthracite coal, quantity of air re- 
quired for combustion of, 337. 
A place for everything, 6. 
Application of balance-weight, 205. 
Arched head, 429. 
Area of a circle, rule for finding, 489. 
Ashes of anthracite, 336. 
Atmosphere, 309. 

column of, 232. 
Atmospheric air, 45. 

pressure, 32. 
Attraction, capillary, 491. 
Available heat of combustion, 336. 
Average atmospheric pressure, 321. 
Axle, 491. 

JSack'action engines. 208. 
Halanced slide-valves, 102. 
JBalancC'iveights, application of,205 
Balancing momentum of direct-act- 
ing engines, 205. 
Barometer, the, 225. 
Beam-centre, relative positions of 

the, 268. 
Beam^-engine, marine, 210, 211. 
Beam^engines, 209. 
Beam pillow-blocks, 266. 
Bedding marine boilers, 405. 
Bed'plate, 74, 212, 271. 

laying of the, 267. 
Belting f 561. 

how to test the quality of leather 
for, 567. 
Belts^ double leather, 565. 

horizontal, 564. 

leather, 564. 

perpendicular, 565. 

rubber, 565. 

583 



584 



INDEX. 



Belts run on the centre of pulleys, 

how to make, 567. 
Bituminous coal, 338. 
JBlasco d* Gar ay, 576. 
Bodies f density of, 321. 
Boiler compound, Lord's, 450. 

explosions, 452. 

feed-pumps, 179. 

flues, 417. 

heads, 429. 

tube- and flue-cleaner, Pike's,573. 

tubular, 352. 
Boilers and boiler materials, defini- 
tions applied to, 469. 

cylinder, 351. 

evaporative efficiency of, 372. 

expansion and contraction of, 
358. 

flue, 352. 

horse-power of, 375. 

locomotive, 353. 

marine, 399. 

of ocean steamers, 224. 

setting, 356. 

steam, 350. 

testing, 359. 
Boiling-point for fresh water at dif- 
ferent altitudes above sea-level, 
306. 

of water, 303. 
Bourne's rule, 69. 
Brace, 269. 
Branca, 576. 
Brass or composition rings, 135. 

to polish, 570. 
Buckeye high-pressure cut-off en- 
gine, 52, 53, 148. 

Calculating weights and measures, 

useful numbers in, 292. 
Calking, 464. 

Connery's concave method of, 
466. 
Caloric, 321. 

engine, Roper's, 159, 324, 325. 

latent, 322. 

radiation of, 322. 

reflection of, 322. 

sensible, 322. 
Cani'punip, Dayton, 181, 



Capacity, unit of, 295. 
Capillary attraction, 491. 
Carbon, 347. 

Carbonate of magnesia, 443. 
Carburetted hydrogen, 347. 
Care and management of steam- 
boilers, 363. 

of marine boilers, 406. 
Cataract, the, 145. 
Cement for making steam-joints and 
patching steam-boilers, 568. 

for rust-joints, 568. 
Centigrade thermometer, 315. 
Central and mechanical forces and 

definitions, 490. 
Centre, dead, 128. 
Centre of gravity, 492. 

of gyration, 495. 

of gyration of counter- welght6,205 

of oscillation, 503. 
CentrC'points, the, 267. 
Centres of the journals, 270. 
Centrifugal action of screw, 277. 

force, 139. 
Change of zero, 316. 
Chemical and mechanical remedies, 
447. 

equivalents, 334. 
Chests, steam, 85. 

Chimney, area of, rule for finding, 
484. 

diameter and height of, table 
showing proper, 484. 
Chimneys, 483. 

Circle, cylinder, sphere, etc., mensu- 
ration of, 487. 

the, 511. 
Circulation of water in boilers, 

effects of heat on, 331. 
Cleanliness, 72. 
Clearance, 99. 

inside, 95. 
Clock, 226. 

Clothing marine boilers, 405. 
Coal, anthracite, 336. 

bituminous, 338. 
Coal-gas, 347. 
Coke, coal, and wood, table showing 

relative properties of, 344. 
. Colburn's rule, 69. 



INDEX. 



585 



Column of atmosphere, 232. 
Conihustiorif 332. 

available heat of, 336. 
spontaneous, 342. 
Co^nniercial horse-power, 62. 
Common slide-valve, 94. 
Communication of heat, 330. 
Comparative scale of Centigrade, 
Fahrenheit, and Reaumer ther- 
mometers, 314. 
strength of single and double 
riveted seams, 461. 
Composition of water, 299. 
Compression^ 100. 

and dilatation of gases, 348. 
Composition of different kinds of 

anthracite coal, 336. 
Compound engine, vertical, 199. 
engines, 200. 
motion, 503. 
Concealed heat of steam, 26. 
Concussive ebullition, 455. 
Condenser, 212, 268. 
jet, 216, 221. 
surface, 217. 
surface, Pirsson's, 218. 
surface, Sewell's, 220. 
Condensers, 216. 

Condensing engine, working prin- 
ciples of, explanation of, 190. 
or low-pressure steam-engine, 

188. 
engines, feed-pump for, 183. 
engines, horse-power of, 191. 
engines, power of, Watts' rule for 
calculating, 191. 
Conditions of equilibrium,, 320. 
to be observed to obtain a correct 
diagram, 239. 
Conical or poppet-valves, 95. 
Connecting»rod, examination of, 
110. 
piston and crank connection, 80. 
Connections, slide-valve, 103. 
Cooling compound for heavy bear- 
ings, 572. 
Corliss high-pressure cut-off engine, 
126. 
high-pressure engine, 151. 
valves, 125. 



Corrosion of marine boilers, 451. 
Counter 'Weights,CQntvQ of gyration 

of, 205. 
Cover, air-pump, 260. 
Crank-circle, subdivision of, 112. 
Crank connection, piston, and con- 
necting-rod, 80. 
Crank, examination of principles 
involved in use of. 111. 
of engine, 80. 
Crank-pin, heating of the, 259. 
table showing angular position 
of, 84. 
Crank-pins, 83. 
Cranks, 109. 
Cross-head, form of, 86. 

slides for the, 269. 
Cross-heads, 86. 
Crowding tubes, 411. 
Cu7'ves, theoretical, 238. 
Curvilinear seams, 470. 
Cut-off engine, Allen high-pressure, 
155, 161. 
Buckeye high-pressure, 52, 53, 

148. 
Hampson and Whitehill's high- 
pressure, 153, 154. 
Hawkins and Dodge's high- 
pressure, 24, 147. 
Watts and Campbell's high- 
pressure, 37, 148. 
Wheelock's high-pressure, 71. 
Woodruff and Beach's high- 
pressure, 156, 168. 
Wright's high-pressure, 20, 146. 
Cut-offs, 105, 138. 
Cycloldal wheels, 283. 
Cylinder boilers, 351. 
bottom, the, 212. 268. 
rule for finding the mean or 
average pressure in a, 50. 
Cylinders, 74. 
horizontal, 242. 
oscillating, 242. 
vertical, 241. 

Dayton cam-pump, 181. 
Dead centre. 128. 
Decimal, 291. 
arithmetic, 291. 



586 



iin>EX. 



Decimal equivalents of inches, feet, 
and yards, 292. 
equivalents of pounds and 

ounces, 292. 
equivalents to the fractional 
parts of a gallon or an inch, 
294. 
fractions, 291. 
J>efects,^7, 
Definitions applied to boilers and 

boiler materials, 469. 
Decrees of temperature, rules for 

comparing, 318. 
Density of bodies, 321., 
Deposits, accumulation of, 459. 
Design of steam-engines. 73. 
Deterioration of plates, 456. 
D'Garay, Blasco, 576. 
Diagram, conditions to be observed 
to obtain a correct, 239. 
how to compute a, 244. 
is taken, how to calculate the 
power the engine is exerting 
when the, 244. 
observ£ition on the character of, 

243. 
No. 1, 238. 
Nos. 2 and 3, 240. 
No. 4, 245. 
No. 5, 247. 
, No. 6, 248. 

Nos, 7 and 8, 249. 
No. 9, 250. 
No. 10, 253. 
Diagram,s are taken, facts to be re- 
corded when, 242. 
form of, 250. 
Diameter and arrangement of tubes, 
411. 
and length of rock-shaft, 86. 
of pump-plunger for an engine, 
rules for finding the, 182. 
Dimensions of steam-ports, 87. 
Direct-acting engines. 203. 
balancing momentum of, 205. 
screw-engine, 204. 
Directions for setting up steam- 
pumps, 184. 
Disconnecting paddle-wheels, 286. 
Domes, steam, 353. 



Double eccentrics on the shaft, for- 
mula by which to find positions 
of, 107. 
leather belts, 565. 
Draft, regulation of, 385. 
Di'ums, mud, 355. 
Dynamic equivalent of heat, 329. 
Dynamics, 492. 
Dynamometer, 254. 
Dynamometrical horse-power, 62. 
or effective horse-power of a 
marine engine, rules for find- 
ing the, 255. 

Ebullition, concussive, 455. 
Eccentric, how to find the throw 
of any, 106. 

throw or stroke of the, 106. 
Eccentric-rod, how to adjust, 109. 

length of, 109. 
EccentriC'rods, 108. 

modes of attaching, 109. 
Eccentirics, 104. 

of marine engines. 106. 
Economical working of steam-en- 
gine, 73. 
Economy in high -pressure engines, 

70. 
Effective pressure against piston, 64. 
Effect of heat on circulation of water 

in boilers, 331. 
Effluent velocity of steam, 32. 
Elastic fluids, 320. 
Elasticity, 470, 

of steam, 27. 
Electricity, 454. 
Electro-magnetism^, 72. 
Energy, 492. 
Engine, Corliss high-pressure, 151. 

crank of, 80. 

Hampson and Whitehill's high- 
pressure, 153. 

Haskin's vertical high-pressure, 
163, 308. 

high-pressure, 158, 319. 

high-pressure, desirable, 55. 

how to reverse an, 31. 

in line, how to put an, 128. 

Massey's rotary, 164, 333. 

Nay lor' s vertical, 300. 



INDEX. 



587 



JEnginCf Naylor's vertical high-pres- 
sure, 157. 
shaft-pulley, to find diameter of 

144. 
steeple, 208. 

vertical compound, 199. 
Williams' vertical three-cylinder, 
300, 319. 
JEngineer, the, 256. 
Engineers* or machinists' tools, 

how to mark, 569. 
Engines f back-action, 208. 
beam, 209. 
compound, 200. 

condensing horse-power of, 191. 
direct-acting, 203. 
geared, 207. • 

in a steamboat or ship, how to 

put the, 265. 
knocking in, 167. 
land and marine, management 

of, 258. 
oscillating, 205. 
portable, 166. 
setting up, 127. 
side-lever, 209. 
small, 63. 
trunk, 207. 

vertical, how to balance, 166. 
Equilibrium, conditions of, 320. 
Equivalents, chemical, 334. 

of inches, feet, and yards, deci- 
mal, 292. 
of pounds and ounces, decimal, 

292. 
to the fractional parts of a gallon 
or an inch, decimal, 294. 
Evans, Oliver, 578, 579. 
Evaporation, 322. 
Evaporative efficiency of a pound 
of anthracite coal, 337. 
boilers, 372. 
tubes, 412. 
Everything In its place, 6. 
Examination of connecting-rod, 
110. 
of the principles involved in the 
use of the crank, 111. 
Exam,ples for finding horse-power 
of steam-engines, 65-69. 



Excessive firing. 459. 
Expansion, 46. 

of air by heat, table showing the, 

312. 
period of, 118. 
Expansive property of steam, 44. 
Explanation of tables of boiler 
pressures, 389. 
working principles of condens- 
ing engine, 190. 
Explosions, boiler, 452. 
Explosive gases, generation of, 455. 
External surfaces of tubes, table of 
superficial areas of, 413. 

Factors, table of, 68. 

Facts to be recorded when diagrams 

are taken, 242. 
Feathering wheel, 284. 
Feed' pumps for condensing en- 
gines, 183. 
Feed'Water heaters, 472. 
Feed'water, temperature of, 176, 177. 
Film or scale, 452. 
Firing, 378. 

excessive, 459. 

instructions for, 382. 
Fitch, John, 578. 
Fitting slide-valves, 103. 
Fixed temperatures, 318. 
Flat-head, 430. 

Flue and tube cleaners, steam-boiler, 
573. 

boiler, marine, 398. 

boilers, 352. 
Flues, boiler, 417. 
Fluid resistance, 287. 
Fluids, elastic, 320. 
Foaming, 439. 

in locomotive boilers, 440. 

in marine boilers, 440. 
Focus, 493. 
Force, 492. 

centrifugal, 139. 

with which steam acts, 57. 
Foreign terms and units for horse- 
power, 59. 
Form of diagrams, 250. 

of cross-head, 86. 

of screw, 274. 



588 



INDEX. 



Formula by which to find positions 
of double eccentrics on the 
shaft, 107. 
Friction, 493. 

of slide-valves, 100. 

rollers, 494. 
Fuel, 46. 

and air, mixture of, 335. 

ingredients of, 335. 

waste of unburnt, 341. 
Fiilton, Robert, 578. 

Gang of steam-boilers, 349. 
GaSf olefiant, 347. 
Gases, 346. 

compression and dilatation of, 
348. 

liquefaction of, 348. 
Gauge, mercury, 231. 

siphon, 231. 

spring, 230. 

vacuum, 226, 230. 
Gauges, steam, 227, 229. 
Geared engines, 207. 
Gearing, 559. 

Generation of explosive gases, 455. 
Glass water-gauges, 233. 
Good material, 72. 

workmahship, 72. 
Governor, Allen, 142, 143. 

Huntoon, 140. 

shaft-pulley, to find diameter of, 
144. 

spindles, 142. 
Governors, 139. 
Grate'bars, 482. 
Gravity acts on gases, 320. 

and gravitation, 494. 

centre of, 492. 

specific, 494. 
Guides, 85. 

strength or stiff'ness of, 86. 
Gum, 572. 
Gyration, centre of, 495. 

Sampson and Whitehill's high- 
pressure cut-off' engine, 153, 
IM. 

Sand rock-shaft or trip-shaft, the, 
214. 



Sard patch, to apply, 409. 
SasMn's vertical high-pressure 

engine, 163, 308. 
Sawkins and Dodge's high-pressure 

cut-off engine, 24, 147. 
Seads, boiler, 429. 

cross, 86. 
Seat, communication of, 330. 

dynamic equivalent of, 329. 

latent, 326. 

mechanical equivalent of, 327. 

mechanical theory of, 328. 

medium, 331. 

molecular or atomic force of, 329. 

of combustion of various fuels, 
table showing the total, 342. 

of water or ice, latent, 301, 302. 

power of expansion by, 329. 

sensible, 327. 

specific, 324. 

table showing the expansion of 
air by, 312. 

total or actual, 330. 

transmission of, 330. 

unit of, 294, 326. 

upon different bodies, table show- 
ing effects of, 332. 
Seater pipe, 367. 
Seaters, feed-water, 472. 
Seating of crank-pin, 259. 

surface of steam-boilers, rule for 
finding the, 371. 

surface to cylinder and grate sur- 
face, etc.. proportions of, 402. 
Seavy bearings, cooling compound 

for, 572. 
Sigh-pressure engine, advantages 
of, 54. 

Corliss, 151. 

desirable, 55. 

economy in, 70. 

Hampson and Whitehill's, 153. 

Raskin's vertical, 163, 308. 

Naylor's vertical, 157. 

Wheelock's, 151. 
High'pressure or non-condensing 

steam-engines, 54. 
Sorizonfal belts, 564. 

cylinders, 242. 

motion, 117. 



INDEX. 



689 



Horizontal tubes, 412. 

tubular marine boiler, 404. 
Mors empower f 495. 

actual or net, 61. 

commercial, 62. > 

dynamometrical, 62. 

foreign terms and units for, 59. 

indicated, 61. 

nominal, 60. 

of boilers, 375. 

of condensing engines, 191. 
How to adjust eccentric rod, 109. 

to balance vertical engines, 166. 

to calculate the power the engine 
is exerting when the diagram is 
taken, 244. 

to compute a diagram, 244. 

to find the throw of any eccentric, 
106. 

to keep indicator in order, 252. 

to line up a propeller shaft, 282. 

to make belts run on the centre 
of pulleys, 567. 

to mark engineers' or machinists' 
tools, 569. 

to put an engine in line, 128. 

to put the engines in a steamboat 
or ship, 265. 

to reverse an engine, 131. 

to set a slide-valve, 132. 

to test the quality of leather for 
belting, 567. 
JEEuntoon governor, 140. 

interior view of working parts of, 
141. 
Hydraulic test, 362. 
Hydrocarbons, 335. 
Hydrodynamics, 496. 
Hydrogen, 346. 

carburetted, 347. 
Hydrometer, salinometer, or salt- 
gauge, the, 223. 
Hyperbola, 496. 
Hyperbolic logarithms, 517. 

table of, 48, 518. 

Ice, specific gravity of, 304. 
Itnmersion of paddles, 286. 
Inipactf 497. 
Impenetrability, 497. 
50 



Impetus, 498. 

Improved methods of lacing belts, 

563. 
Incidence, 498. 
Inclination, 498. 
Inclined plane, 498, "501. 
Incrustation in steam-boilers, 441. 
Indicated horse-power, 61. 
Indicator in order, how to keep 
the, 252. 
method of applying, 241. 
Richards', 235. 
steam-engine, 235. 
utility of the, 244. 
Indices, the, 317. 
Inertia, 498. 
Ingredients of fuel, 335. 
Injection and condensed water, rel- 
ative quantities of, 219. 
Injector, the, 168. 

adjustable, method of working, 

173. 
adjustable, Sellers', 174. 
Giffards', with Sellers' improve- 
ment, 169. 
self-adjusting, method of work- 
ing, 172. 
Sellers' self-adjusting, 171. 
Injectors, instructions for setting 
up, 173. 
table of capacities of, 177. 
Inside clearance, 95. 
Instructions for firing, 382. 

for setting up injectors, 173. 
Interior view of working parts of 

Huntoon governor, 141. 
Internal and external corrosion of 
steam-boilers, 449. 
radius, 470. 
Invention and improvement of the 

steam-engine, 574. 
Inverted siphon, 231. 



fJachPts, steam, 474. 
James Watt, 187, 577. 
Jet condenser, 221. 
John Fitch, 578. 
Joints, 571. 

red-lead, 571. 
Journals, centres of the, 



270. 



590 



INDEX. 



Knocking in engines, 167. 

Lacing belts, improved methods of, 

563. 
Zand and marine engines, manage- 
ment of, 258. 
Zap on the slide-valve, 93. 

required for slide-valves of sta- 
tionary engines, table showing 
amount of, 97. 
Zatent caloric, 322. 

heat, 326. 

heat of steam, 26. 

heat of various substances, 331. 

heat of water or ice, 301, 302. 
Zaying of bed-plate, 267. 
Zead of the slide-valve, 97. 
Zead-wire, 572. 
Zeahage of air, 261. 
Zeather belts, 564. 
Zength of eccentric-rod, 109. 

unit of, 294. 
Zeopold and Trevithick, 577. 
Zevel the shaft, 130. 
ZeverSf 499. 

safety-valve, 4S6. 
Zift of conical or poppet-valves, 96. 
Zime, sulphate of, 443. 
Zinear expansion of wrought-iron, 

548. 
ZArik-niotion, 116, 260. 
Ziqtiefaction of gases, 348. 
Zoad on piston-rod, 121. 
Zocomotive boilers, 853. 

foaming in, 440. 
ZogarithniSf 515. 

from to 1000, 516. 

hyperbolic, 517. 
Zongitudinal and curvilinear 
strains, 387. 

seams, 470. 
Zord's boiler compound, 450. 
Zoss of pressure in cylinders induced 

by long steam-pipes, 475. 
Zuhricating steam-cylinders, 479. 

thorough, 72. 

Machines, 499. 
Magnesia, carbonate of, 443. 
Magnetic water-gauges, 234. 



Magnetism, electro, 72. 
3Iain and out-port pillow>blocks, 
placing of the, 270. 

bearings or pillow-blocks, 114. 

shaft and out-port pillow-blocks, 
setting of the, 269. 
3Ianagement of land and marine 

engines, 258. 
Manley paddle-wheel, 285. 
Manner of placing a straight-edge, 

265. 
Manometer, the, 224. 
Marine beam-engine, 210, 211. 

boiler, horizontal tubular, 404. 

flue boiler, 398. 

boiler, vertical tubular, 407. 

boilers, 899. 

bedding, 405. 

care of, 406. 

clothing, 405. 

corrosion of, 451. 

setting, 404. 
MarinC'Cngine register, clock, and 

vacuum gauge, 226. 
Marine^engines, eccentrics of, 106. 

starting-gear for, 215. 
Marine steam-engines, 197, 198. 
Marquis of Worcester, 576. 
Mass, 500. 

Massey's rotary engine, 164, 333. 
Material, good, 72. 
Matter, 500. 
Measurement of screw-propeller, 

279. 
Mechanical equivalent of heat, 327. 

power, 287. 

power, amount of, 288. 

powers, 500. 

pressure, 29. 

properties of vapor, 25. 

theory of heat, 328. 
Mechanics, 502. 
Medium heat, 351. 
Mensuration of the circle, cylin- 
der, sphere, etc., 487. 
Mercurial thermometer, 313. 
Mercury -gauge, 231. 
Mercury, properties of, 313. 

rate of expansion of, 315. 
Meters, 374. 



INDEX. 



591 



Method of applying the indicator, 
?41. 
of determining how much power 
each tenant is actually using, 
244. 
of working adjustable injector 
when required to lift water, 
173. 
of working self-adjusting injector 
when required to lift water, 172. 
Mlnar causes of loss in steam- 
engines, 70. 
Mixture of fuel and air, 335. 
Modes of attaching eccentric-rods, 

109. 
3Todulus, 502. 
Molecular or atomic force of heat, 

329. 
Momentunif 502. 
Motion, 502. 
absolute, 502. 
accelerated, 503. 
angular, 503. 
compound, 503. 
horizontal, 117. 
link, 116. 
natural, 503. 
of slide-valve, 90. 
of steam, 35. 
parallel, 503. 
perpetual, 505. 

proper points from which to de- 
rive the, 242. 
relative, 503. 
retarded, 503. 
rotary, 104. 
uniform, 503. 
Movers f prime, 507. 
Mud'drutnSf 355. 
Multipliers, table of, 51. 
Murdoch, 579. 

Natural motion, 503. 
Nature of valve motion, 91. 
Natjlor^s vertical high-pressure en- 
gine, 157, 300. 
Negative slip of the screw-propeller, 

' 274. 
Neglect of steam-boilers, 362. 
Net or actual horse-power, 61. 



Neweomen, 577. 
Nitrogen, 348. 

Nominal horse-power, 60. 
Nou'condiicto?' for steam-pipes and 
steam-cylinders, 569. 

Observations on character of dia- 
gram, 243. 
Ocean steamers, boilers of, 224. 
Oil or tallow, 262. 
Oils and oiling, 477. 
Olefiant gas, 347. 
Oliver Evans, 578, 579. 
Ordinary radial wheel, 283. 
Oscillating cylinders, 242. 

engines, 205. 
Oscillation, centre of, 503. 
Overheating, 458. 
Overpressure, 458. 

JPacJcing, piston, and valve-rod, 135. 
Paddle-wheel, Manley, 285. 
Paddle-wJieels, 282. 

disconnecting, 286. 
Paddles, immersion of, 286. 
Paddle-shaft, the, 286. 
Parallel motions, 503. 

rods. 580. 
Parts of long-stroke side-valve en- 
gines, 88. 
Pendulum, 504. 
Percussion, 504. 
Period of expansion, 118. 
Perpendicular belts, 565. 
Perpetual motion, 505. 
PiJce^s boiler, tube, and flue cleaner, 

573. 
Pillow blocks, beam, 266. 

or main bearings, 114. 
Pin, rock-shaft, 86. 
Pins, crank, 83. 

Pirsson^s surface condenser, 218. 
Piston, 212, 260. 

and valve-rod packing, 135. 

connecting-rod, crank connec- 
tion, 80. 

eflective pressure against, 64. 

in cylinder at ditferent crank- 
angles, table showing the posi- 
tion of, 81. 



592 



INDEX. 



Piston packing, setting out, 134. 

rings, 77. 

rod, load on, 121. 

rods, 83. 

speeds for all classes of engines, 
table of, 79. 

speeds, table showing proper area 
of steam-ports for different, 88. 

springs, 77. 

stroke of, 92. 
JPistonSf 76. 

of steam-hammers, 79. 

solid, 78. 

steam, 78. 
Pitch of a screw, 274. 
Placing air-pump in its seat, 271. 

of the main and outport pillow- 
blocks, 270. 
Plane, inclined, 498. 501. 
Plates, deterioration of, 456. 
Pneumatics, 506. 
Points, the centre, 267. 
Poppet or conical valves, 95. 
Portable engines, 166. 
Power, 507. 

in the steam-engine, 196. 

mechanical, 287, 500. 

of a horse, 495. 

of expansion by heat, 329. 

of steam, 113. 

of steam-engine, 55. 
Pressure and temperature of steam, 
30. 

average atmospheric, 321. 

of air, 310. 

of steam, 28. 

of steam on piston, 113. 

unit of, 297. 
Pressures for iron boilers, table of 
safe internal, 390. 

steel boilers, table of safe inter- 
nal. 394. 
Prime movers, 507. 
Priming in steam-cylinders, 476. 
Proi^eller shaft, how to line up, 282. 
Propellers, screw, 271. 
Proper points from which to derive 
motion, 242. 

proportions of screw - propellers, 
table of, 279. 



Properties of mercury, 313. 
Proportions of heating surface to 
cylinder and grate surface, etc., 
402. 

of slide-valves, 93. 

of steam-cylinder, 124. 

of steam-engines, 121 
Pulsometer, the, 185. 
Pumps, 178. 

air, 222. 

boiler feed, 179. 

steam, 180. 

Madial wheel, 282. 

Radiating power of different bodies, 

table of, 331. 
Radiation of caloric, 322. 
Radius, internal, 470. 
Raising steam and getting under 

way, 263. 
Rate of expansion of mercury, 315. 
Reaumer's thermometer, 316. 
Red-lead joints, 571.* 
Reflection of caloric, 322. 
Register, marine engine, 226. 

thermometers, 317. 
Regulation of draft, 385. 
Relative motion, 503. 

positions of the beam-centre, 268. 

quantities of injection and con- 
densed water, 219. 
Remedies, chemical and mechan- 
ical, 447. 
Repairing steam-boilers, 409. 
Resistance, fluid, 287. 

of tubes, 410. 
Resisting pressure, amount of, 201. 
Retarded motion, 503. 
Richard's indicator, 235. 
Rings, brass or composition, 135. 

piston, 77. 
Robert Fulton, 579. (Frontispiece.) 
Rock-shaft, 86. 

diameter and length of, 86. 

pin, 86. 

the hand, 214. 
Rods, eccentric, 108. 

parallel, 580. 

piston, 83. 

valve, 85. 



INDEX. 



593 



Mollers, friction, 494. 

Boper's caloric engine, 159, 324, 325. 

Motarif engine, Massey's, 333. 

motion, 104. 
Mubber belts, 566. 

Jtule for ascertaining amount of 
benefit derived from working 
steam expansively, 48. 

Bourne's, 69. 

Colburn's. 69. 

for calculating horse-power of 
steam-engine, 68. 

for calculating the number of 
horse-powers a belt will trans- 
mit, etc., 567. 

for finding area of a circle, 489. 

for finding aggregate strain, etc., 
on shells of steam-boilers, 389. • 

for finding centre of gravity of 
taper levers for safety-valves, 
439. 

for finding change required in 
the length of a belt, etc., 566. 

for finding collapsing pressure of 
boiler flues, 424. 

for finding horse-power of steam- 
engine, 65. 

for finding necessary quantity of 
water per minute for any en- 
gine, 183. 

for finding pressure, at which a 
safety-valve is weighted, 438. 

for finding pressure per square 
inch, etc., 437. 

for finding safe external pressure 
on boiler flues, 418. 

for finding safe working pressure 
of iron boilers, 388. 

for finding safe working pressure 
of steel boilers, 388. 

for finding weight necessary to 
put on a safety-valve, etc., 437. 

for finding the mean or average 
pressure in a cylinder^^50. 

for finding the length of belt 
wanted, 566. 

for finding the number of revolu- 
tions of the last wheel in a train 
of wheels and pinions, etc., 560. 



Mule for finding the required amount 
of lap for slide-valve corres- 
ponding to any desired point of 
cut-off", 96. 

for finding the required area of 
chimney for any boiler, 484. 

for finding the required diameter 
of cylinder for an engine of 
any given horse - power, the 
travel of piston and available 
pressure being decided upon, 
76. 
Mules for calculating size of pulleys 
for governors, 144. 

for comparing degrees of tempe- 
rature indicated by different 
thermometers, 318. 

for finding the diameter and 
speed of pulleys, 558. 

for finding the diameter of tooth- 
ed wheels, 559. 

for finding the diameter of a pin- 
ion, etc., 559. 

for finding the diameter of pump- 
plunger for any engine, 182. 

for finding the dynamometrical 
or effective horse -power of a 
marine engine, 255. 

for finding the effects of mechan- 
ical powers, 501. 

for finding the heating surface of 
steam-boilers, 371. 

for finding the number of revolu- 
tions of a pinion or driven, 
etc., 560. 

for finding the number of revolu- 
tions of a driver, etc., 560. 

for finding the number of revolu- 
tions of the last wheel at the 
end of a train of spur-wheels, 
etc., 560. 

for finding the number of revolu- 
tions in each wheel for a train 
of spur-wheels, etc.. 560. 

for finding the pressure on slide- 
valves, 101. 

for finding the quantity of water 
boilers, etc., are capable of con- 
taining, 386, 387. 



50* 



2N 



594 



INDEX. 



Mules for finding the required num- 
ber of teeth in a pinion, etc., 559. 
for finding the width of belt to 
transmit a given horse-power, 
566. 
JRust joints, 571. 
cement for, 568. 

Safe external pressure on boiler 
flues, rule for finding the, 418. 

working - pressure or safe load, 
470. 
Safety-valve, the, 367. 

levers, 436. 
Safety-valves, 431. 

table showing use of, 433. 
Salinometer or salt-gauge, 223. 
Salt'gauge or salinometer, 223. 
Saturated steam, 32. 
Screw, 501. 

as compared with the paddle, 278. 

centrifugal action of, 277. 

engine, direct-acting, 204. 

form of, 274. 

pitch of a, 274. 

propeller, measurement of, 279. 

propeller, negative slip of the' 
274. 

propeller, surface of a, 279. 

propellers, 271. 

propellers, proper proportion of, 
table of the, 279. 
Screws, twin, 278. 
Seains, curvilinear, 470. 

longitudinal, 470. 
Sea-water, 224. 
Section of Roper's caloric engine, 

325. 
Self-adjusting injector, method of 

working the, 172. 
Sellers^ self-adjusting injector, 171. 

adjustable injector, 174. 
Sensible caloric, 322. 

heat, 327. 
Set poppet or conical valves, 133. 
Setting boilers, 356. 

marine boilers, 404. 

of main shaft and out-port pillow- 
blocks, 269. 

out piston packing, 134. 



Setting up engines, 127. 

up injectors, instructions for, 173. 

valves, 131. 
SewelVs surface condenser, 220. 
Shaft, level the, 130. 

wear of the, 73. 
Shafts, crank, 114. 

rock, 86. 
Side-lever engines, 209. 

pipes, the, 213. 
Signification of signs used in cal- 
culations, 291. 
Signs used in calculations, significa- 
tion of, 291. 
Single- and double-riveted seams, 

comparative strength of, 461. 
Siphon, inverted, 231. 
Siphon-gauge, 231. 
Size of pulleys for governors, rules 

for calculating the, 144. 
Slides for the cross-head, 269. 
Slide-valve, 580. 

common, 94. 

connections of, 103. 

corresponding to any desired 
point of cut-off, rule for finding 
the required amount of lap for 
a, 96. 

engines, ports of long stroke, 88. 

how to set a, 132. 

lap on the, 93. 

lead of the, 97. 

motion of, 90. 
Slide-valves, S9. 

balanced, 102. 

fitting, 103. 

friction of, 100. 

proportions of, 93. 

rule for finding the pressure on, 
101. 
Slip of the screw-propeller, negative, 

274. 
Small engines, 63. 
Smoke, 485. 
Soapstone, 136. 
Soft patch, the, 410. 
Solder, 570. 
Solid pistons, 78. 

thermometers, 318. 
Solvents, 448. 



INDEX. 



595 



Sound test, 362. 
Specific gravity, 494. 

gravity of ice, 304. 

gravity of water, 304. 

heat, 324. 
Spheroidal theory, 456. 
Spindles, governor, 142. 
Spirit thermometers, 318. 
Spontaneous combustion, 342. 
Spring'ffange, the, 230, 581. 
Springs, piston, 77. 
Starting 'gear for marine engines, 

215. 
Statics, 507. 
Stay-bolts, 468. 
Steam, 25. 

atmospheric pressure of, 32. 

at different pressures, table show- 
ing temperature and weight of, 
39-43. 

effluent velocity of, 32. 

elasticity of, 27. 

expansive property of, 44. 

latent or concealed heat of, 26. 

mechanical pressure of, 29. 

motion of, 35. 

on piston, pressure of, 113. 

power of, 113. 

pressure of, 28. 

saturated, 32. 

superheated, 34. 

temperature and pressure of, 30. 

Upon piston, table showing aver- 
age pressure of, 45, 50. 

volume and weight of, 35. 

water while passing into, 29. 
Steam-boiler, flue, and tube Clean- 
ers, 573. 
Steam-boilers, 350. 

care and management of, 363. 

gang of, 349. 

incrustation in, 441. 

internal and external corrosion 
of, 449. 

neglect of, 362. 

repairing, 409. 
Steam-chest, 85, 213. 
Steam,-cy Under, proportions of, 124. 

thickness of, 122. 
Steam-cylinders^ lubricating, 479. 



Steam,-cylinders of different diam- 
eters table showing proper 
thickness for, 75. 
priming in, 476. 
thickness of, 75. 
Steam domes, 353. 
Steam-engine, 21. 

economical working of, 73. 

indicator, 235. 

invention and inprovement of 

the, 574. 
minor causes of loss in, 70. 
power in the, 196. 
power of, 55. 
rule for calculating horse-power 

of, 68. 
theory of the, 298. 
valuable features of, 73. 
waste in, 70. 
Steam^-engines, condensing or low- 
pressure; 188. 
design of, 73. 
high-pressure or non-condensing, 

54. 
marine, 197, 198. 
proportions of, 121. 
rule for finding horse-power of, 

65. 
variety of designs of, 74. 
Steam-gauges, 227, 229. 
hammers, pistons of, 79. 
jackets, 474. 
joints and patching steam-boilers, 

cement for making, 568. 
lever, 214. 

pipes and steam-cylinders, non- 
conductors for, 569. 
pistons, 78. 
Steam-ports, dimensions of, 87. 

value, 87. 
Steatn-pumps, 180. 

directions for setting up, 184. 
Steam-room, 401. 
Steeple-engine, the, 208. 
Straight-edge, manner of placing, 

265. 
Strains, longitudinal and curvi- 
linear, 387. 
Strength of stayed and flat surfaces. 
408. 



596 



INDEX. 



Strength or stiffness of guides, 86. 
Stroke and number of revolutions 
for different piston speeds in 
feet per minute, table showing 
length of, 82. 
of piston, 92. 
Subdivision of crank-circle, 112. 
Substances, latent heat of, 331. 
Sulithate of lime, 443. 
Superheated steam, 34. 
Surface condenser, Pirsson's, 218. 
Sewell's, 220. 
unit of, 295. 

Table containing diameters, circum- 
ferences, and areas of circles, 
etc., 511. 

containing diameters, circum- 
ferences, and areas of circles 
from yig- of an inch to 100 
inches, etc., 521. • 

deducted from experiments on 
iron plates for steam-boilers, 
etc., 470. 

of capacities of injectors, 177. 

of coefficients of frictions be- 
tween plane surfaces, 480. 

of comparison between experi- 
mental results and theoretical 
formulae, 435. 

of factors, 68. 

of hyperbolic logarithms, 48, 518. 

of multipliers, 51. 

of piston speeds for all classes of 
engines. 79. 

of proper proportions of screw- 
propellers, 279. 

of radiating power of different 
bodies, 331. 

of safe internal pressures for iron 
boilers, 390. . 

of safe internal pressures for steel 
boilers, 394. 

of safe working external press- 
ures on flues ten feet long, 
420. 

of safe working external pressures 
on flues twenty feet long, 422. 

of squares, cubes, and square and 
cube roots, etc., 532. 



Table of squares of thicknesses of 
iron, etc., 419. 

of superficial areas of external 
surfaces of tubes, etc., 413. 

of temperatures, etc., 845. 

showing actual extension of 
wrought-iron at various tem- 
peratures, 548. 

showing amount of lap required 
for slide-valves of stationary 
engines, etc., 97. 

showing angular position of 
crank-pin, 84. 

showing average pressure of 
steam upon piston, 49, 50. 

showing boiling-point for fresh 
water at different altitudes 
above sea-level, 306. 

showing effects of heat upon dif- 
ferent bodies, 332. 

showing length of stroke and 
number of revolutions for dif- 
ferent piston speeds, etc., 82. 

showing nature and value of va- 
rieties of American coal and 
coke, etc., 343. 

showing position of piston in cyl- 
inder at different crank-angles, 
81. 

showing prominent qualities in 
principal American woods, 344. 

showing proper area of steam- 
ports for different piston speeds, 
88. 

showing proper diameter and 
height of chimney for any kind 
of fuel, 484. 

showing proper thickness for 
steam-cylinders of different di- 
ameters, 75. 

showing relative properties of 
good coke, coal, and wood, 344. 

showing result of experiments 
made on different brands of 
boiler-iron, etc., 471. 

showing rise of safety-valves, etc., 
at different pressures, 433. 

showing temperature and weight 
of steam at different pressures, 
39-43. 



INDEX. 



597 



Table showing tensile strength of 
various qualities of cast-iron 
plates, 549. 

showing tensile strength of vari- 
ous qualities of steel plates, 
549. 

showing tensile strength of vari- 
ous qualities of wrought-iron, 
547. 

showing the expansion of air by 
heat, etc., 312. 

showing the units of heat, etc., 
473. 

showing total heat of combustion 
of various fuels, 342. 

showing weight of atmosphere 
in pounds, etc., 311. 

showing weight of boiler-plates 
one foot square, etc., 551. 

showing weight of cast-iron balls * 
etc., 553. 

showing weight of cast-iron pipes 
one foot in length, etc., 554. 

showing weight of different ma- 
terials, 571. 

showing weight of round bar- 
iron, etc., 552. 

showing weight of square bar- 
iron, 551. 

showing weight of water, 305. 

showing weight of water at dif- 
ferent temperatures, 305. 

showing weight of water in pipe, 
etc., 307. 

showing weight per square foot 
of wrought-iron, steel, copper, 
and brass, 555. 
Tables of collapsing pressure of 
wrought-iron boiler-flues, etc., 
425, 428. 
Tallow or oil, 462. 

Temperature and pressure of steam, 
30. 

of feed-water, 176, 177. 
Temperatures f fixed, 318. 

underground, 318. 
Tendency to overheating, 446. 
Tensile strength, 469. 
Test, hydraulic, 362. 

sound, 362. 
Testing boilers, 359. 



Theoretical curve, 238. 
Theory of the steam-engine, 298. 
Thermometer, 313. 

centigrade, 315. 

mercurial, 313. 

Reaumer's, 316. 
TJiermometers, comparative scale 
of Centigrade, Fahrenheit, and 
Reaumer, 314. 

register, 317. 

spirit, 318. 

solid. 318. 
Thickness of steam - cylinders, 75, 

122. 
Thorough lubrication, 72. 
Tltrow or stroke of the eccentric, 106. 
Tighteners, 567. 
Time or duration, unit of, 296. 
To find diameter of engine -shaft 
pulley, 144. 

find diameter of governor shaft- 
pulley, 144. 

polish brass, 570. 

set poppet or conical valves, 133. 
Tools, 508. 
Torsion, 508. 
Total or actual heat, 330. 
Transmission of heat, 330. 
TrevithicTc and Leopold, 577. 
Trip'Shaft or hand rock-shaft, the 

214. 
TrunJc'Cngines, 207. 
Tubes, crowding, 411. 

diameter and arrangement of, 411. 

evaporative efficiency of, 412. 

horizontal, 412. 

resistance of, 410. 

use of, 410. 
Tubular boiler, 352. 
Twin»screws, 278. 

Underground temperatures, 318. 
Uniform motion, 503. 
Unit of capacity, 295. 

of heat, 294. 

of length, 294. 

of pressure, 297. 

of surface, 295. y 

of time or duration, 296. 

of velocity, 297. 

of weight, 296. 



598 



INDEX. 



U7iit of work, 297. 
TTnitSf 294. 
Z^se of tubes, 410. 

Useful numbers in calculating 
weights and measures, etc., 292. 
TJtility of indicator, 244. 

Vacuum, 193. 

gauge, 226, 230. 
Valuable features of steam-engine, 

73. 
Value of steam-ports, 87. 
Valve-gear, 213. 

motion, nature of, 91. 

rods, 85. 

slide, 580. 
Valves f 213. 

Corliss, 125. 

lift of conical or poppet, 96. 

poppet, or conical, 95. 

safety, 431. 

setting the, 131. 

to set poppet or conical, 133. 
Vapor, mechanical properties of, 25. 
Variety of designs of steam-engines, 

74. 
Velocity, 508. 

unit of, 297. 
Vertical compound engine, 199. 

cylinders. 241. 

engines, how to balance, 166. 

tubular marine boiler, 407. 
Volume and weight of steam 35. 

Waste in the steam-engine, 70. 

of unburnt fuel, 31. 
Water, 299. 

boiling-point of, 303. 

composition of. 299. 
Water-gauges, glass, 233. 

magnetic, 234. 
Watevf necessary quantity of, rule 
for finding, 133. 

passing into steam, 29. 

specific gravity of, 304. 

weight of, table showing, 305. 
Watt, James, 187, 577. 
Watt and Campbell's high-pressure 

cut-off engine, 37, 481. 
WatVs rule for calculating power of 
condensing engines, 191. 



Wear of the shaft, 73. 
Wedge, 501. 
Weight, 509. 

and volume of steam, 35. 

of atmosphere in pounds, etc., 

table showing the, 311. 
of cast-iron plates per superficial 

foot as per thickness, 553. 
of shafting, etc., calculating the, 

552. 
of water at different temper- 
atures, table showing the, 305. 
of water in pipe, etc., table show- 
ing the, 307. 
unit of, 296. 
Weights and measures, 509. 
Wheel and axle, 501. 
feathering, 284. 
ordinary radial, 283. 
radial, 282. 
Wheelock's high-pressure cut-off 

engine, 71, 151. 
Wheels, cycloidal, 283. 
fly, 115. 
paddle, 282. 
Williams' three - cylinder engine, 
319. 
vertical three - cylinder high- 
pressure engine, 158, 319. 
Woodruff and Beach's high -pressure 

cut-off engine, 156, 165. 
Worcester, Marquis of, 576. 
Work, 510. 

unit of, 297. 
Working-beam, 211. 
Working steam expansively, 43. 

strength, 469. 
Wo7'kmanday, 510. 
Workmanship, good, 72. 
Wright's high-pressure cut-off en- 
gine, 20, 146. 
Wrought'iron at various temper- 
atures, table showing actual 
extension of, 548. 
linear expansion of, 548. 
various qualities of, taJble show- 
ing tensile strength of, 547. 

Zero, absolute, 316. 
change of, 316. 



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Trautwine's New MetJiod of Calculating the Cubic Contents of 

Evacuations and Embankments by the aid of Diagrams ; together 
with Directions for Estimating the cost of Earthwork. By JOHN 
C. Trautwine, Civil Engineer. 10 steel plates. Fifth edition, 
completely revised and enlarged. 8vo, cloth. $2.00. 

Trautwine's Field- Practice of T^aying out Circular Cu/rves for 
Mailroads. By JoHN C. TRAUTWINE. Civil Engineer. Ninth 
edition, revised and enlarged. 12mo, tuck. $2.00. 

Any of the above Books will be sent by mail, free of postage, on 
receipt of publication price, by CLAXTON, REMSEN & HAFFEL- 
FINGER, 624, 626 & 628 Market Street; or, STEPHEN POPER, 
447 North Broad Street, Philadelphia. ^fl^ 

Information by letter, wheji asked for, will be cheerfully ^ven 
to parties making inquiry aboi^t scientific books. A stamp and an 
addressed envelope shoujd, in all cases, accompany such inquiries. 
^4 (^ 600 



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